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1) VG2 NEP CRS CALIB RDR D1 RATE HI RESOLUTION ELEC 6SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/CRS/Neptune/PT6S
Start:1989-08-25 05:08:50 Observatory:Voyager 2 Cadence:6 seconds
Stop:1989-08-25 05:21:02 Instrument:Cosmic Ray System (CRS) Resource:NumericalData
Data Set Overview ================= This data set describes the data of the high time resolution counting rate from the D1 detector in the Cosmic Ray System (CRS) electron telescope (TET) on Voyager 2 during the Neptune encounter. The D1 detector nominally responds to electrons with kinetic energies above approximately 1 MeV (see detector description for details). Parameters ========== Sampling parameter name : time Sampling parameter resolution : 6.0 seconds Minimum sampling parameter : n/a Maximum sampling parameter : n/a Sampling parameter interval : 6.0 seconds Minimum available sampling interval : 6.0 seconds Data set parameter name : D1 rate Noise level : 0.000 counts/second Data set parameter unit : counts/second The D1 rate is the counting rate from the D1 detector of the Cosmic Ray System (CRS) electron telescope (TET). When the rate is above background it is approximately proportional to the omnidirectional flux of electrons with kinetic energy greater than ~1 MeV. To obtain an accurate flux the D1 calibration tables should be used (see below). When the rate is near background, the background rate should be subtracted. The background rate is due to gamma rays generated in the spacecraft RTG and to penetrating cosmic rays. It varies slightly with time on the time scale of months, but is generally near 25 counts per second. When the rate is near saturation, corrections for discriminator deadtime should be made. The discriminator deadtime is approximately 20 micro-seconds (it varies slightly with the electron energy spectrum), so that the saturation level is approximately 50,000 counts per second. When the correction is near a factor of two or less a reliable corrected rate can be obtained from the formula {corrected rate} = {uncorrected rate}/(1+deadtime*{uncorrected rate}) When the deadtime correction is substantially larger than a factor of two, reliable corrections are not available. In this case, electron pileup and baseline shift may also be important, which may increase or decrease the expected rate. The data points are 6 second averages taken once every 96 seconds. Table 1 below provides the D1 response function R(E,theta) which is a function of electron energy E in MeV (column at left) and angle theta in degrees from the TET axis (row at top). Each table entry is R in cm**2 for the corresponding E and theta. The D1 electron rate is related to the differential intensity j(E,alpha) in (cm**2 s sr MeV)**-1, where alpha is the electron pitch-angle, by integrating the product R*j over E and solid angle. Note that the angle between the TET axis and the local magnetic field direction is also required. The D1 RATE is then obtained by adding the background rate and applying the inverse of the deadtime correction described above. At energies above the maximum provided R can be approximated by the value at the highest provided energy. At angles above the maximum provided R can be approximated by zero. ------------------------------------------------------------------- Table 1. D1 response function ------------------------------------------------------------------- | 11. 15. 23. 32. 41. 51. 61. ------------------------------------------------------------------- | 0.618 | 0.014 0.005 0.007 0.007 0.006 0.003 0.001 0.801 | 0.151 0.134 0.103 0.087 0.038 0.016 0.008 0.989 | 1.384 1.440 1.219 0.998 0.610 0.311 0.143 1.179 | 2.233 2.402 2.095 1.796 1.255 0.689 0.380 1.372 | 2.829 2.938 2.593 2.241 1.636 0.956 0.583 1.567 | 3.212 3.283 2.936 2.536 1.940 1.167 0.724 1.763 | 3.495 3.534 3.206 2.772 2.161 1.356 0.860 1.959 | 3.708 3.705 3.404 2.964 2.357 1.495 0.969 2.157 | 3.620 3.790 3.452 3.053 2.427 1.602 1.049 2.355 | 3.995 3.948 3.576 3.231 2.617 1.758 1.155 2.553 | 4.096 4.091 3.735 3.395 2.735 1.875 1.263 2.752 | 4.154 4.098 3.808 3.426 2.792 1.927 1.298 2.951 | 4.043 4.054 3.727 3.371 2.819 1.951 1.339 3.150 | 3.946 4.029 3.700 3.335 2.648 1.956 1.358 3.350 | 3.876 4.194 3.611 3.573 2.863 1.927 1.290 ------------------------------------------------------------------- Table 1. D1 response function (continued) ------------------------------------------------------------------- | 70. 80. 90. 100. ------------------------------------------------------------------- 0.618 | 0.002 0.001 0.000 0.000 0.801 | 0.010 0.007 0.004 0.001 0.989 | 0.163 0.095 0.047 0.018 1.179 | 0.386 0.217 0.113 0.056 1.372 | 0.526 0.301 0.163 0.087 1.567 | 0.617 0.366 0.201 0.117 1.763 | 0.679 0.413 0.241 0.146 1.959 | 0.730 0.461 0.270 0.179 2.157 | 0.760 0.484 0.296 0.207 2.355 | 0.809 0.518 0.329 0.242 2.553 | 0.836 0.551 0.363 0.292

2) VG2 NEP CRS RESAMPLED SUMMARY D2 RATE ELEC 96SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/CRS/Neptune/PT96S
Start:1989-08-24 22:00:00 Observatory:Voyager 2 Cadence:96 seconds
Stop:1989-08-25 10:00:00 Instrument:Cosmic Ray System (CRS) Resource:NumericalData
Data Set Overview ================= Counting rate from the D2 detector in the Cosmic Ray System (CRS) electron telescope (TET) on Voyager 2 during the Neptune encounter. The D2 detector nominally responds to electrons with kinetic energies above approximately 2.5 MeV (see detector description for details). Parameters ========== Sampling parameter name : time Sampling parameter resolution : 6.0 seconds Minimum sampling parameter : n/a Maximum sampling parameter : n/a Sampling parameter interval : 96.0 seconds Minimum available sampling interval : 96.0 seconds Data set parameter name : D2 rate Noise level : 0.000 counts/second Data set parameter unit : counts/second The D2 detector is located behind the D1 detector in the TET telescope, so that most of the electrons observed by D2 have to penetrate D1 first. The D2 rate therefore applies to higher energy electrons and the threshold energy is less distinct than for D1, but is near 2.5 MeV. The rate can be calculated from the electron differential flux in the same way as the D1 RATE (see D1 RATE description) with the following calibration table. ------------------------------------------------------------------- Table 1. D2 response function ------------------------------------------------------------------- | 11. 23. 41. 61. 80. 90. 100. ------------------------------------------------------------------- 0.989 | 0.000 0.000 0.000 0.001 0.002 0.001 0.001 1.179 | 0.000 0.000 0.000 0.013 0.023 0.021 0.018 1.372 | 0.000 0.000 0.000 0.037 0.052 0.051 0.043 1.567 | 0.000 0.019 0.028 0.063 0.082 0.066 0.061 1.763 | 0.041 0.034 0.045 0.090 0.111 0.098 0.080 1.959 | 0.106 0.078 0.072 0.119 0.142 0.125 0.097 2.157 | 0.255 0.186 0.127 0.152 0.170 0.146 0.109 2.355 | 0.488 0.381 0.228 0.206 0.212 0.176 0.126 2.553 | 0.772 0.627 0.361 0.272 0.255 0.202 0.139 2.752 | 1.019 0.864 0.501 0.340 0.299 0.226 0.152 2.951 | 1.220 1.053 0.634 0.400 0.335 0.250 0.165 3.150 | 1.461 1.218 0.746 0.459 0.375 0.289 0.188 3.350 | 1.628 1.378 0.940 0.515 0.456 0.411 0.282 Processing ========== The ENCYCLOPEDIA GENERATOR program was run by Nand Lal at Goddard Space Flight Center to read the EDR tape, check for error conditions, and reformat the data to generate a CRS encyclopedia tape. The resulting tape was sent to CalTech for subsequent data analysis. The VCRUSH program was run at CalTech to select data of interest from CRS encyclopedia tapes. In the case of counting rate data, no further analysis was done to produce the data in the PDS data sets. Note: Neither the ENCYCLOPEDIA GENERATOR or VCRUSH software are available for public use.

3) VG2 NEP TRAJECTORY DERIVED SUMM NLS COORDS 12SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/Ephemeris/Neptune/PT12S
Start:1989-08-24 18:00:00 Observatory:Voyager 2 Cadence:12 seconds
Stop:1989-08-26 08:19:48 Instrument:Voyager 2 Positions Resource:NumericalData
Data Set Overview ================= This dataset contains Voyager 2 spacecraft position vectors relative to Neptune in minus NLS coordinates. The NLS or Neptune West Longitude System coordinate system is a planetocentric system fixed to Neptune which is rotating with a 16.11 hour period. The NLS coordinate system is defined as follows: - X lies in the equatorial plane of Neptune, positive away from the planet, and through the prime meridian. - Z is parallel to the Neptune spin axis, and, - Y is X x Z (lefthanded) The prime meridian of the this system is defined such that at 1989-08-25T03:56:00.000 the Voyager 2 spacecraft was at 167.7 degrees west longitude. For the PDS archive dataset, the original data archive has been converted to an east longitude (righthanded) coordinate system minus NLS (-NLS). This is achieved by reversing the direction of the Y-axis or in spherical coordinates, subtracting the NLS longitude from 360.0 degrees. The data are provided in units of Neptune radii which was taken to be 24,765km by the Voyager project. Angles are given in degrees. Both cartesian and spherical coordinates are provided. Parameters ========== Sampling parameter name : time Sampling parameter resolution : 12.0 seconds Minimum sampling parameter : n/a Maximum sampling parameter : n/a Sampling parameter interval : 12.0 seconds Minimum available sampling interval : 12.0 seconds Data set parameter name : position vector Noise level : n/a Data set parameter unit : Neptune radii (24,765km) or degrees Coordinates =========== Neptune West Longitude System (NLS) Coordinates ----------------------------------------------- Coordinate System Center Name = NEPTUNE Coordinate system Ref Epoch = UNK /* 1989-08-25:03:56:00.000 */ The orientation of Neptune's pole is specified by a right ascension of 298.90 and declination of 42.84 at the time of the encounter, as given in the Jet Propulsion Laboratory's distribution of physical constants dated 11/06/89. Planetary longitudes are based on a 16.11 hour rotation period (Warwick et al., 1989) adopted by the Voyager Project shortly after the encounter. The zero longitude is defined by the requirement that the West Longitude of the spacecraft at 0356 SCET day 237 (near closest approach) be 167.7 NLS; West Longitudes of the Neptune Longitude System (NLS) are simply related to the angle PHI: WLONG = 360. - PHI (degrees) This definition of the zero longitude was adopted by the Voyager Project Steering Group in order to minimize differences in longitudes resulting from changes in the assumed rotation period. Position is given in terms of the following: RANGE (R) - Range from the planet center to the spacecraft in units of Rn where Rn = 24,765km. LATITUDE (LAT) - Spacecraft latitude in degrees. Valid range -90.0 -> +90.0. LONGITUDE (W_LONG) - West longitude where the zero longitude is defined by the requirement that the West Longitude of Voyager 2 at 1989-08-25T03:56:00.00 was 167.7 degrees.

4) VG2 NEP TRAJECTORY DERIV SUMM HELIOGRAPHIC COORDS 48SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/Ephemeris/Neptune/PT48S
Start:1989-08-22 00:00:47 Observatory:Voyager 2 Cadence:48 seconds
Stop:1989-08-29 23:59:58 Instrument:Voyager 2 Positions Resource:NumericalData
Data Set Overview ================= This dataset contains Voyager 2 position vectors relative to the Sun in both cartesian and spherical Heliographic coordinates for the time period when Voyager was near Neptune but not within its magnetosphere. The magnetospheric gap in this dataset occurs from 1989-08-25 02:00 -> 1989-08-26 00:00. Spacecraft position vectors are given in Neptune Longitude System (NLS) coordinates in this interval. The position vectors are given every 48 seconds. The units of the vector components are Au and degrees. Vectors are stored as 4-byte floating point values. The Heliographic coordinate system is defined in the reference epoch of 1950. The unit vectors which define the coordinate system are as follows: X points away from the Sun toward the ascending node, in the solar equatorial plane, Z points along the Sun's spin axis, positive above the equatorial plane, and Y completes the right handed set. Parameters ========== Sampling parameter name : time Sampling parameter resolution : 96.0 seconds Minimum sampling parameter : n/a Maximum sampling parameter : n/a Sampling parameter interval : 48.0 seconds Minimum available sampling interval : 48.0 seconds Data set parameter name : position vector Noise level : n/a Data set parameter unit : AU or degrees Coordinates =========== MEAN INERTIAL HG 1950 --------------------- COORDINATE_SYSTEM_CENTER_NAME = SUN COORDINATE_SYSTEM_REF_EPOCH = UNK /* 09-23-1950 */ The Heliographic coordinate system is defined in the reference epoch of 1950. The unit vectors which define the coordinate system are as follows: X points away from the Sun towards the ascending node, in the solar equatorial plane, Z points along the Sun's spin axis, positive above the equatorial plane, and Y completes the right handed set. Position is given in terms of the following: RANGE (R) - The range or R component of the spherical Heliographic coordinate system is the distance from the Sun's position at the reference epoch to the spacecraft measured in AU. LATITUDE (LAT) - The latitude component of the spherical Heliographic coordinate system is the angle between the solar equatorial plane of the reference epoch measured in the plane that contains the solar spin axis of that epoch. LONGITUDE (LONG) - The longitude component of the spherical Heliographic coordinate system is zero in the direction of the ascending node at the reference epoch (X direction) and increases for a body orbiting the Sun as the Earth does. X - The X component of the Heliographic coordinate system points away from the Sun, towards the ascending node, and lies in the solar equatorial plane. Y - The Y vector of the Heliographic coordinate system is formed by the righthanded cross product of the X and Z unit vectors. It lies in the solar equatorial plane and it points away from the Sun, but does not extend in the direction of any particular body. Z - The Z component of the Heliographic coordinate system is parallel to the Sun's spin axis, taken as positive above the equatorial plane of the Sun.

5) VG2 LECP 0.4S HIGH RESOLUTION NEPTUNE FAR ENCOUNTER DATA maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/LECP/Neptune/PT0.400S
Start:1989-08-24 00:00:23 Observatory:Voyager 2 Cadence:0.400 seconds
Stop:1989-08-28 00:00:20 Instrument:Low-Energy Charged Particles (LECP) Resource:NumericalData
Data Set Overview ================= Data Set Description -------------------- This far encounter data set consists of electron and ion counting rate data from the Low Energy Charged Particle (LECP) experiment on Voyager 2 while the spacecraft was within the vicinity of Neptune. This instrument measures the intensities of in-situ charged particles ( >13 keV electrons and >24 keV ions) with various levels of discrimination based on energy range and mass species. A subset of almost 100 LECP channels are included in this data set. The LECP data are globally calibrated to the extent possible. During Neptune far encounter, the entire LEPT (Low Energy Particle Telescope) and part of the LEMPA (Low Energy Magnetospheric Particle Analyzer) subsystems were turned on for data collection. Particles include electrons, protons, alpha particles, and light, medium, and heavy nuclei particles. The far encounter data are 0.4 second rate measurements within 1/8 of the LECP instrumental motor rotation period (the angular scanning periods, or step period). The LECP instrument has a rotating head for obtaining angular anisotropy measurements of the medium energy charged particles. A gear-drive motor steps through eight equal angular sectors per revolution for data collection. The cycle time for the rotation is 48 minutes or 25.6 minutes during cruise mode, and 192 second or 48 second during the planetary encounter. The data were originally collected in the form of 'rates', which were not always converted into the usual physical units. The reason is that such a conversion would depend on uncertain determinations such as the mass species of the particles and the level of background. Both mass species and background are generally determined from context during the study of particular regions. To convert 'rate' to 'intensity' for a particular channel one performs the following tasks: 1) decide on the level of background contamination and subtract that off the given rate level. Background is to be determined from context and from making use of sector 8 rates (sector 8 is covered by a 2 mm Aluminium sunshield and used for data calibration). 2) Divide the background corrected rate by the channel geometric factor and by the energy bandpass of the channel. To determine the energy bandpass, one must judge the mass species of the detected particles (for ions but not for electrons). The energy band passes are given in the form of 'energy/nucleon'. For channels that begin their names with the designations 'ch' these bandpasses can be used on mass species that are accepted into that channel, which gives the minimum and maximum 'Z' value accepted -- these entries are blank for electron channels). For other channels the given bandpass refers only to the lowest 'Z' value accepted. The bandpasses for other 'Z' values are not all known, but some are given in the literature (e.g. [KRIMIGISETAL1979A]). The final product of these instructions will be the particle intensity in the unit of 'counts/(cm**2 sr sec keV)'. LECP data can also be in the form of flux, whose unit is 'cm**-1 sr**-1 sec**-1'. Far Encounter Channel Definitions for Voyager 2 LECP CH CH LOW HIGH MEAN GEOMETRIC CH Num NAME (MeV/N) (MeV/N) (Mev/N) FACTOR LOGIC cm**2 sr DEFINITIN -------------------------------------------------------- 1 EB01 0.013 0.035 0.020 0.00200 2 EBD1 0.013 0.035 0.020 0.00200 3 EB02 0.035 0.061 0.045 0.00200 4 EBD2 0.035 0.061 0.045 0.00200 5 EB03 0.061 0.112 0.090 0.00200 6 EBD3 0.061 0.112 0.090 0.00200 7 EB04 0.112 0.183 0.120 0.00200 8 EBD4 0.112 0.183 0.120 0.00200 9 EB05 0.183 0.500 0.200 0.00200 10 EBD5 0.183 0.500 0.200 0.00200 11 EG06 0.252 2.000 0.250 0.00200 12 EG07 0.480 2.000 0.500 0.00200 13 EG08 0.853 2.000 0.900 0.00200 14 EG09 2.100 5.000 2.000 0.00200 15 E44 0.350 1.500 0.500 1.31000 16 E45 2.000 100.000 2.000 1.31000 17 E37 6.000 100.000 6.000 1.31000 18 PL01 0.024 0.048 0.025 0.12000 19 PL02 0.048 0.080 0.050 0.12000 20 PL03 0.080 0.137 0.100 0.12000 21 PL04 0.137 0.215 0.150 0.12000 22 PL05 0.215 0.540 0.250 0.12000 23 PL06 0.540 0.990 0.600 0.12000 24 PL07 0.990 2.140 1.000 0.12000 25 PL08 2.140 3.500 2.500 0.12000 26 P32 0.330 0.610 0.350 0.09750 E0E2(E3) 27 P1 0.520 1.450 0.600 0.44100 E1E2(E3) 28 P10 4.400 11.400 5.000 0.53900 E2E3(E4) 29 P11 11.400 20.000 12.000 0.53900 E2E3(E4) 30 P16 3.040 17.000 5.000 1.50000 E5E4(E3) 31 P23 22.000 30.000 25.000 1.31000 E5E4E3(E2) 32 P27 37.000 89.000 50.000 1.20000 E5E4E3E2 33 P31 213.000 1000.000 250.000 1.31000 E4E3 34 A39 0.091 0.233 0.100 0.09750 E0(E2) 35 A33 0.230 0.480 0.350 0.09750 E0E2(E3) 36 A46 0.147 2.000 0.600 0.44100 'D1F1,CA' 37 A3 0.420 1.700 0.600 0.44100 E1E2(E3) 38 A4 1.800 4.000 2.500 0.44100 E1E2(E3L12) 39 A12 4.200 7.800 5.000 0.53900 E2E3(E4L23) 40 A13 7.800 20.000 15.000 0.53900 E2E3(E4L23) 41 A17 3.000 58.000 5.000 1.50000 E5E4(E3L54) 42 A24 22.000 30.000 25.000 1.31000 E5E4E3(E2) 43 A28 31.000 56.000 50.000 1.20000 E5E4E3E2 44 AL01 1.040 1.850 1.000 0.12000 CALC. 45 AL02 1.850 3.700 2.500 0.12000 CALC. 46 M34 0.230 0.440 0.200 0.09750 E0E2 47 L5 0.710 5.600 1.500 0.44100 E1E2(E3L12) 48 L14 5.800 28.000 6.000 0.53900 E2E3(E4L23) 49 L18 3.900 20.000 5.000 1.50000 E5E4(E3L54) 50 M38 0.060 0.200 0.100 0.09750 E0(E2) 51 M35 0.200 0.340 0.250 0.09750 E0E2(E3) 52 M47 0.124 14.300 0.250 0.44100 D1F2 53 M6 0.470 5.200 0.500 0.44100 E1E2(E3L12) 54 M7 5.200 8.200 6.000 0.44100 E1E2(E3L12) 55 M15 8.600 40.000 15.000 0.53900 E2E3(E4L23) 56 M19 6.000 9.200 6.000 1.50000 E5E4(E3L54) 57 M20 9.600 42.000 15.000 1.50000 E5E4(E3L54) 58 M25 44.000 61.000 50.000 1.31000 E5E4E3(E2) 59 M29 69.000 270.000 70.000 1.20000 E5E4E3E2 60 H36 0.099 0.140 0.100 0.09750 E0(E2) 61 H8 0.280 1.900 0.350 0.44100 E1E2(E3) 62 H9 2.000 12.000 2.000 0.44100 E1E2(E3) 63 H43 11.800 74.000 15.000 0.53900 E2E3(E4) 64 H21 8.200 17.000 10.000 1.50000 E5E4(E3L54) 65 H22 18.000 82.000 25.000 1.50000 E5E4(E3L54) 66 H26 86.000 120.000 100.000 1.31000 E5E4E3 67 H30 127.000 1000.000 150.000 1.20000 E5E4E3E2 68 AR SINGLES 69 E0 SINGLES 70 E1 SINGLES 71 E2

6) VG2 LECP 12.8 MINUTE NEPTUNE FAR ENCOUNTER STEP DATA maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/LECP/Neptune/PT12M48S
Start:1989-08-24 12:12:00 Observatory:Voyager 2 Cadence:12 minutes; 48 seconds
Stop:1989-08-26 23:44:00 Instrument:Low-Energy Charged Particles (LECP) Resource:NumericalData
Data Set Overview ================= Data Set Description -------------------- This far encounter step data set consists of the counting rate and flux data for electrons and ions from the Low Energy Charged Particle (LECP) experiment on Voyager 2 while the spacecraft was within the vicinity of Neptune. This instrument measures the intensities of in-situ charged particles ( >13 keV electrons and >24 keV ions) with various levels of discrimination based on energy range and mass species. A subset of almost 100 LECP channels are included in this data set. The LECP data are globally calibrated to the extent possible. During Neptune far encounter, the entire LEPT (Low Energy Particle Telescope) and part of the LEMPA (Low Energy Magnetospheric Particle Analyzer) subsystems were turned on for data collection. Particles include electrons, protons, alpha particles, and light, medium, and heavy nuclei particles. The far encounter data are 12.8 minute rate and flux measurements within 1/8 of the LECP instrumental motor rotation period (the angular scanning periods, or step period). The LECP instrument has a rotating head for obtaining angular anisotropy measurements of the medium energy charged particles. A gear-drive motor steps through eight equal angular sectors per revolution for data collection. The cycle time for the rotation is 48 minutes or 25.6 minutes during cruise mode, and 192 second or 48 second during the planetary encounter. The data were originally collected in the form of 'rates', which were not always converted into the usual physical units. The reason is that such a conversion would depend on uncertain determinations such as the mass species of the particles and the level of background. Both mass species and background are generally determined from context during the study of particular regions. To convert 'rate' to 'intensity' for a particular channel one performs the following tasks: 1) decide on the level of background contamination and subtract that off the given rate level. Background is to be determined from context and from making use of sector 8 rates (sector 8 is covered by a 2 mm Aluminium sunshield and used for data calibration). 2) Divide the background corrected rate by the channel geometric factor and by the energy bandpass of the channel. To determine the energy bandpass, one must judge the mass species of the detected particles (for ions but not for electrons). The energy band passes are given in the form of 'energy/nucleon'. For channels that begin their names with the designations 'ch' these bandpasses can be used on mass species that are accepted into that channel, which gives the minimum and maximum 'Z' value accepted -- these entries are blank for electron channels). For other channels the given bandpass refers only to the lowest 'Z' value accepted. The bandpasses for other 'Z' values are not all known, but some are given in the literature (e.g. [KRIMIGISETAL1979A]). The final product of these instructions will be the particle intensity in the unit of 'counts/(cm**2 sr sec keV)'. LECP data can also be in the form of flux, whose unit is 'cm**-1 sr**-1 sec**-1'. Far Encounter Channel Definitions for Voyager 2 LECP CH CH LOW HIGH MEAN GEOMETRIC CH Num NAME (MeV/N) (MeV/N) (Mev/N) FACTOR LOGIC cm**2 sr DEFINITIN -------------------------------------------------------- 1 EB01 0.013 0.035 0.020 0.00200 2 EBD1 0.013 0.035 0.020 0.00200 3 EB02 0.035 0.061 0.045 0.00200 4 EBD2 0.035 0.061 0.045 0.00200 5 EB03 0.061 0.112 0.090 0.00200 6 EBD3 0.061 0.112 0.090 0.00200 7 EB04 0.112 0.183 0.120 0.00200 8 EBD4 0.112 0.183 0.120 0.00200 9 EB05 0.183 0.500 0.200 0.00200 10 EBD5 0.183 0.500 0.200 0.00200 11 EG06 0.252 2.000 0.250 0.00200 12 EG07 0.480 2.000 0.500 0.00200 13 EG08 0.853 2.000 0.900 0.00200 14 EG09 2.100 5.000 2.000 0.00200 15 E44 0.350 1.500 0.500 1.31000 16 E45 2.000 100.000 2.000 1.31000 17 E37 6.000 100.000 6.000 1.31000 18 PL01 0.024 0.048 0.025 0.12000 19 PL02 0.048 0.080 0.050 0.12000 20 PL03 0.080 0.137 0.100 0.12000 21 PL04 0.137 0.215 0.150 0.12000 22 PL05 0.215 0.540 0.250 0.12000 23 PL06 0.540 0.990 0.600 0.12000 24 PL07 0.990 2.140 1.000 0.12000 25 PL08 2.140 3.500 2.500 0.12000 26 P32 0.330 0.610 0.350 0.09750 E0E2(E3) 27 P1 0.520 1.450 0.600 0.44100 E1E2(E3) 28 P10 4.400 11.400 5.000 0.53900 E2E3(E4) 29 P11 11.400 20.000 12.000 0.53900 E2E3(E4) 30 P16 3.040 17.000 5.000 1.50000 E5E4(E3) 31 P23 22.000 30.000 25.000 1.31000 E5E4E3(E2) 32 P27 37.000 89.000 50.000 1.20000 E5E4E3E2 33 P31 213.000 1000.000 250.000 1.31000 E4E3

7) VG2 NEP LECP RESAMPLED SUMMARY SCAN AVERAGED 24SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/LECP/Neptune/PT24S
Start:1989-08-24 00:00:00 Observatory:Voyager 2 Cadence:24 seconds
Stop:1989-08-27 00:00:00 Instrument:Low-Energy Charged Particles (LECP) Resource:NumericalData
Description of the PDS LECP Neptune Scan data. This data consists of resampled data from the Low Energy Charged Particle (LECP) Experiment on the Voyager 2 Spacecraft for the period when Voyager 2 was in the vicinity of the planet Neptune. The period covered is 1989-08-24T00:00:00.000 SCET to 1989-08-27T00:00:00.000 SCET. This data approximates a time series of charged particle fluxes from a selection of channels available from the instrument. The word approximates is used because the angle scanning modes of the instrument complicates the nature of the data. At times the instrument mechanically scans, and at times it is fixed to look at a specific direction. With the type of data given here, the fluxes are angle averaged for those time periods when the instrument is scanning, and are time averaged over an arbitrary period (12 or 24 sec, see below) for the periods when the detectors are stationary. The angle averaged records represent periods of time equal to 48 or 96 sec (see below). This kind of data presentation has been called the LECP Scan data. Another form that is also available is the LECP Step data that gives the angle distributions sampled during the scanning periods. Three scanning situations occurred during the time of this data. They are: 1) continuous 48 sec stepping (48 seconds for each of 8 look directions for a total of 6.4 minutes per scan; note that sector 8 is shielded with 2 mm Al), 2) a special Neptune scan cyclic with the following sequence: 7, scan, 1, scan, 7, scan, scan, repeat; where the 7 and the 1 represent 5.2 minute periods when the instrument is fixed in sectors 7 or 1, respectively, and where the word scan represents a period of scanning (6 sec stepping for a total scan time of 48 sec); and 3) periods when the detectors are fixed for more extended periods in sector 7 (periods bracketing the ring plane crossings). For this Neptune Scan data, the 6.4 minute scan records during stepping mode (1) have been time averaged to 12.8 minute records. Also, during stepping mode (2), the double scans that have no fixed periods between them have been averaged together into a single (96 sec) record. The single scans represent 48 sec records. The schedule for the three stepping modes is as follows: prior to day 236/1600 SCET: Mode (1) 236/1600 to 237/0239: Mode (2) 237/0239 to 237/0319: Mode (3) 237/0319 to 237/0503: Mode (2) 237/0503 to 237/0554: Mode (3) 237/0554 to 238/0400: Mode (2) after 237/0400: Mode (1) Obviously these stepping mode changes, and the angle sample switching that occurs during stepping mode (2), gives the data a disjointed appearance. Two channel sample modes also occurred during the Neptune encounter. These two modes affect this data set only by changing the primary record time length for the LECP Experiment Data Records (EDR's). These time lengths have, in turn, been utilized for the averaging times of this data set for non-stepping periods. The schedule is: prior to day 237/0200 SCET: Far Encounter (24 sec records) 237/0200 to 237/0551: Near Encounter (12 sec records) after 237/0551: Far Encounter (24 sec records) The LECP channels utilized with this data set are: EB01: electrons, 22 to 35 keV EB02: electrons, 35 to 61 keV EB03: electrons, 61 to 112 keV EB04: electrons, 112 to 183 keV EG06-EG07: electrons, 252 to 480 keV EG07-EG08: electrons, 480 to 853 keV EG08-EG09: electrons, 853 to 1200 keV PL01: ions, 28 to 43 keV PL02: ions, 43 to 80 keV PL03: ions, 80 to 137 keV PL04: ions, 137 to 215 keV PL05: ions, 215 to 540 keV PL06: ions, 540 to 990 keV PL07: ions, 990 to 2140 keV PL08: ions, 2140 to 3500 keV Please note that 3 of the electron channels are derived from 4 of the instrumental channels by taking differences between adjacent (in energy) channels. The channel data is given in units of intensity: counts/(cm^2.sec.str.keV). For the ions, it has been assumed that they consist only of protons. Intensity is derived from the raw count rates via the relation: I = CR/(eG.(E2-E1), where eG is geometric factor times detector efficiency, and (E2-E1) is the band pass of the channel in energy. The proton values of these parameters were used in deriving the intensities for this data set. To obtain the Intensities under the assumption that some other mass species dominates, one must convert back to count rate (CR) utilizing the proton parameters, and then convert to intensity using the parameters corresponding to the

8) VG2 LECP 3.2 MINUTE NEPTUNE FAR ENCOUNTER STEP DATA maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/LECP/Neptune/PT3M
Start:1989-08-23 19:55:59 Observatory:Voyager 2 Cadence:3 minutes
Stop:1989-08-26 23:53:11 Instrument:Low-Energy Charged Particles (LECP) Resource:NumericalData
Data Set Overview ================= Data Set Description -------------------- This far encounter step data set consists of the counting rate and flux data for electrons and ions from the Low Energy Charged Particle (LECP) experiment on Voyager 2 while the spacecraft was within the vicinity of Neptune. This instrument measures the intensities of in-situ charged particles ( >13 keV electrons and >24 keV ions) with various levels of discrimination based on energy range and mass species. A subset of almost 100 LECP channels are included in this data set. The LECP data are globally calibrated to the extent possible. During Neptune far encounter, the entire LEPT (Low Energy Particle Telescope) and part of the LEMPA (Low Energy Magnetospheric Particle Analyzer) subsystems were turned on for data collection. Particles include electrons, protons, alpha particles, and light, medium, and heavy nuclei particles. The far encounter data are 3.2 minute rate and flux measurements within 1/8 of the LECP instrumental motor rotation period (the angular scanning periods, or step period). The LECP instrument has a rotating head for obtaining angular anisotropy measurements of the medium energy charged particles. A gear-drive motor steps through eight equal angular sectors per revolution for data collection. The cycle time for the rotation is 48 minutes or 25.6 minutes during cruise mode, and 192 second or 48 second during the planetary encounter. The data were originally collected in the form of 'rates', which were not always converted into the usual physical units. The reason is that such a conversion would depend on uncertain determinations such as the mass species of the particles and the level of background. Both mass species and background are generally determined from context during the study of particular regions. To convert 'rate' to 'intensity' for a particular channel one performs the following tasks: 1) decide on the level of background contamination and subtract that off the given rate level. Background is to be determined from context and from making use of sector 8 rates (sector 8 is covered by a 2 mm Aluminium sunshield and used for data calibration). 2) Divide the background corrected rate by the channel geometric factor and by the energy bandpass of the channel. To determine the energy bandpass, one must judge the mass species of the detected particles (for ions but not for electrons). The energy band passes are given in the form of 'energy/nucleon'. For channels that begin their names with the designations 'ch' these bandpasses can be used on mass species that are accepted into that channel, which gives the minimum and maximum 'Z' value accepted -- these entries are blank for electron channels). For other channels the given bandpass refers only to the lowest 'Z' value accepted. The bandpasses for other 'Z' values are not all known, but some are given in the literature (e.g. [KRIMIGISETAL1979A]). The final product of these instructions will be the particle intensity in the unit of 'counts/(cm**2 sr sec keV)'. LECP data can also be in the form of flux, whose unit is 'cm**-1 sr**-1 sec**-1'. Far Encounter Channel Definitions for Voyager 2 LECP CH CH LOW HIGH MEAN GEOMETRIC CH Num NAME (MeV/N) (MeV/N) (Mev/N) FACTOR LOGIC cm**2 sr DEFINITIN -------------------------------------------------------- 1 EB01 0.013 0.035 0.020 0.00200 2 EBD1 0.013 0.035 0.020 0.00200 3 EB02 0.035 0.061 0.045 0.00200 4 EBD2 0.035 0.061 0.045 0.00200 5 EB03 0.061 0.112 0.090 0.00200 6 EBD3 0.061 0.112 0.090 0.00200 7 EB04 0.112 0.183 0.120 0.00200 8 EBD4 0.112 0.183 0.120 0.00200 9 EB05 0.183 0.500 0.200 0.00200 10 EBD5 0.183 0.500 0.200 0.00200 11 EG06 0.252 2.000 0.250 0.00200 12 EG07 0.480 2.000 0.500 0.00200 13 EG08 0.853 2.000 0.900 0.00200 14 EG09 2.100 5.000 2.000 0.00200 15 E44 0.350 1.500 0.500 1.31000 16 E45 2.000 100.000 2.000 1.31000 17 E37 6.000 100.000 6.000 1.31000 18 PL01 0.024 0.048 0.025 0.12000 19 PL02 0.048 0.080 0.050 0.12000 20 PL03 0.080 0.137 0.100 0.12000 21 PL04 0.137 0.215 0.150 0.12000 22 PL05 0.215 0.540 0.250 0.12000 23 PL06 0.540 0.990 0.600 0.12000 24 PL07 0.990 2.140 1.000 0.12000 25 PL08 2.140 3.500 2.500 0.12000 26 P32 0.330 0.610 0.350 0.09750 E0E2(E3) 27 P1 0.520 1.450 0.600 0.44100 E1E2(E3) 28 P10 4.400 11.400 5.000 0.53900 E2E3(E4) 29 P11 11.400 20.000 12.000 0.53900 E2E3(E4) 30 P16 3.040 17.000 5.000 1.50000 E5E4(E3) 31 P23 22.000 30.000 25.000 1.31000 E5E4E3(E2) 32 P27 37.000 89.000 50.000 1.20000 E5E4E3E2 33 P31 213.000 1000.000 250.000 1.31000 E4E3

9) VG2 LECP 6 MINUTE NEPTUNE STEP DATA maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/LECP/Neptune/PT6M
Start:1989-08-19 19:55:59 Observatory:Voyager 2 Cadence:6 minutes
Stop:1989-09-02 19:53:10 Instrument:Low-Energy Charged Particles (LECP) Resource:NumericalData
TBD

10) VG2 NEP MAG RESAMP RDR HELIOGRAPHIC COORDINATES 1.92SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/MAG/Neptune/PT1.92S
Start:1989-08-22 00:00:47 Observatory:Voyager 2 Cadence:1.92 seconds
Stop:1989-08-29 00:00:44 Instrument:Triaxial Fluxgate Magnetometer (MAG) Resource:NumericalData
Data Set Overview ================= This data set includes data from the Low Field Magnetometer (LFM) during the inbound Neptune encounter beginning in the solar wind and continuing until the first magnetopause crossing. The magnetometer are given in Heliographic coordinates and the data have been averaged from the 60ms instrument sample rate to a 1.92 second resampled rate. The dataset consists of the following columns: 1) ctime (decimal seconds since 1966-01-01T00:00:00.000), 2) pdstime (ISO standard time format), 3-5) spacecraft clock (m65536,m60,fds-line), 6) magnetometer id (1 = LFM, 2 = HFM), 7), Br (radial component), 8) Bt (tangential component), 9) Bn (normal component), 10) Bmag (magnitude of the average components), 11) avg_Bmag (average of the magnitude of the raw components), 12) Lambda (longitude = tan^-1(Bt/Br)), 13) Delta (latitude = sin^-1(Bn/avg_Bmag) ), 14-16) rms vector (Pythagorean root mean square deviation of the component averages), 17) npts (number of points in average), 18) flag a character string which indicates software or s/c hardware intervention which reduces confidence in the data (NULL flags represent 'good' data). Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : 0.06 seconds Minimum Sampling Parameter : 0.06 seconds Maximum Sampling Parameter : 0.06 seconds Sampling Parameter Interval : 1.92 seconds Minimum Available Sampling Interval : 1.92 seconds Data Set Parameter Name : magnetic field vector Noise Level : 0.006 nT Data Set Parameter Unit : nanotesla Magentic field vector: A derived parameter which combines the 3 orthogonal magnetic field component measurements. Measured Parameters ------------------- Magentic field component: A measured parameter equaling the magnetic field strength (e.g. in nanoteslas) along a particular axis direction. Usually the three orthogonal axis components are measured by three different sensors. Ancillary Data ============== An ancillary data file containing the derived spacecraft magnetic field is provided with this data at a 48 second sample rate. These data provide zero level offsets used in the data processing. S/C field data is provided in spacecraft coordinates. Coordinate System ================= Mean Inertial Heliographic 1950 (HG) Coordinates ------------------------------------------------ COORDINATE_SYSTEM_CENTER_NAME : SUN COORDINATE_SYSTEM_REFERENCE_EPOCH : UNK /* 09-23-1950 */ The Heliographic coordinate system is defined in the reference epoch of 1950. The unit vectors which define the coordinate system are as follows: X points away from the Sun toward the ascending node, in the solar equatorial plane, Z points along the Sun's spin axis, positive above the equatorial plane, and Y completes the right handed set. Position is given in terms of the following: RANGE (R) - The range or R component of the spherical Heliographic coordinate system is the distance from the Sun's position at the reference epoch to the spacecraft measured in AU. LATITUDE (LAT) - The latitude component of the spherical Heliographic coordinate system is the angle between the solar equatorial plane of the reference epoch measured in the plane that contains the solar spin axis of that epoch. LONGITUDE (LONG) - The longitude component of the spherical Heliographic coordinate system is zero in the direction of the ascending node at the reference epoch (X direction) and increases for a body orbiting the Sun as the Earth does. X - The X component of the Heliographic coordinate system points away from the Sun, towards the ascending node, and lies in the solar equatorial plane. Y - The Y vector of the Heliographic coordinate system is formed by the righthanded cross product of the X and Z unit vectors. It lies in the solar equatorial plane and it points away from the Sun, but does not extend in the direction of any particular body.

11) VG2 NEP MAG RESAMPLED SUMMARY NLS COORDINATES 12SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/MAG/Neptune/PT12S
Start:1989-08-24 18:00:00 Observatory:Voyager 2 Cadence:12 seconds
Stop:1989-08-26 08:19:48 Instrument:Triaxial Fluxgate Magnetometer (MAG) Resource:NumericalData
Data Set Overview ================= The Voyager magnetometer investigation (P.I.- Norman F. Ness) makes available archival data through the National Space Science Data Center (NSSDC) located at NASA/GSFC as well as through the Planetary Data System (PDS) and other channels. The primary archive format, referred to as a 'summary tape' or 'conjoint summary tape' has been used consistently since the beginning of the Voyager mission to the outer planets (1977). This format makes available magnetometer observations, supplementary engineering and ephemeris data in one data file, and it is one product of Voyager magnetometer routine data processing. Users are referred to the summary format data for all data requirements with one exception: Neptune encounter high field observations. Neptune close approach observations are archived separately and in a different format from that with which many are familiar. This high-field archive is described here. The special demands of the Neptune encounter flyby exceeded (finally) the capabilities of the routine data processing system conceived and implemented in the mid 1970's. As a result, it was necessary to implement an additional data processing system with which the near-encounter, high field magnetometer observations were processed. The data products avail- able with this new data processing system are not available in the same format as the standard Voyager magnetometer observations; thus the need for a separate archive and a new format description. We appreciate the desirability of a consistent archive format, but find no reasonable alternative to the present solution. We expect, however, that users interested in near encounter observations will find this new format both useful and easy to assimilate. The magnetic fields investigation on Voyager carries a total of four tri-axial ring core fluxgate magnetometers: two identical high field magnetometers mounted on the spacecraft body (HFM's) and two identical low field magnetometers (LFM's) arranged on a 13 m boom (Behannon et al., 1977). The two LFM's automatically step through a total of eight dynamic ranges (ranges 0 through 7) in response to changes in the measured field, starting with a nominal dynamic range of 8 nT, and increasing to a nominal dynamic range of 50,000 nT. The two HFM's each operate in two dynamic ranges (ranges 0 and 1) with nominal values of 50,000 nT and 200,000 nT. In the Neptune encounter mode, each magnetometer was sampled periodically with a temporal resolution of between 0.600 s and 0.060 s, and analog-to-digital converted with 12 bit resolution for subsequent telemetry. The magnitude of the maximum observed field at Neptune (approximately 10,000 nT) was sufficiently large that data from all four of the magnetometers proved useful. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : 12.0 seconds Minimum Sampling Parameter : 19770820120000.000000 Maximum Sampling Parameter : UNK Sampling Parameter Interval : 12.0 seconds Minimum Available Sampling Interval : 0.060000 seconds Data Set Parameter Name : magnetic field vector Noise Level : 0.006000 nT Data Set Parameter Unit : nanotesla Magentic field vector: A derived parameter which combines the 3 orthogonal magnetic field component measurements. Measured Parameters ------------------- Magentic field component: A measured parameter equaling the magnetic field strength (e.g. in nanoteslas) along a particular axis direction. Usually the three orthogonal axis components are measured by three different sensors. Data ==== 1) MAGNETOMETER DATA PRODUCT ctime - Decimal seconds past 1966-01-02T00:00:00 (an internal time format) SCET - Spacecraft event time PDS/ISO standard time format. B_R - Magnetic field vector radial component in units of nanotesla; planetocentric right-handed spherical coordinate system. B_THETA - Magnetic field vector theta component, units nanotesla. B_PHI - Magnetic field vector phi component, units nanotesla. The vector magnetic field is rendered in a right handed spherical coordinate system in which the angles THETA and PHI are the usual polar angles, with THETA (colatitude) measured from the axis of rotation and PHI increasing in the direction of rotation. The orientation of Neptune's pole is specified by a right ascension of 298.90 and declination of 42.84 at the time of the encounter, as given in the Jet Propulsion Laboratory's distribution of physical constants dated 11/06/89. Planetary longitudes are based on a 16.11 hour rotation period (Warwick et al., 1989) adopted by the Voyager Project shortly after the encounter. The zero longitude is defined by the requirement that the West Longitude of the spacecraft at 0356 SCET day 237 (near closest approach) be 167.7 NLS; West Longitudes of the Neptune Longitude System (NLS) are simply related to the angle PHI: WLONG = 360. - PHI (degrees)

12) VG2 NEP MAG RESAMP SUMMARY HELIOGRAPHIC COORDS 48SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/MAG/Neptune/PT48S
Start:1989-08-22 00:00:47 Observatory:Voyager 2 Cadence:48 seconds
Stop:1989-08-29 23:59:58 Instrument:Triaxial Fluxgate Magnetometer (MAG) Resource:NumericalData
Data Set Overview ================= This data set includes data from the Low Field Magnetometer (LFM) during the inbound Neptune encounter beginning in the solar wind and continuing until the first magnetopause crossing. The magnetometer are given in Heliographic coordinates and the data have been averaged from the resample 9.6 second sample rate to a 48.0 second rate. The dataset consists of the following columns: 1) ctime (decimal seconds since 1966-01-01T00:00:00.000), 2) pdstime (ISO standard time format), 3-5) spacecraft clock (m65536,m60,fds-line), 6) magnetometer id (1 = LFM, 2 = HFM), 7), Br (radial component), 8) Bt (tangential component), 9) Bn (normal component), 10) Bmag (magnitude of the average components), 11) avg_Bmag (average of the magnitude of the raw components), 12) Lambda (longitude = tan^-1(Bt/Br)), 13) Delta (latitude = sin^-1(Bn/avg_Bmag) ), 14-16) rms vector (Pythagorean root mean square deviation of the component averages), 17) npts (number of points in average), 18) flag a character string which indicates software or s/c hardware intervention which reduces confidence in the data (NULL flags represent 'good' data). Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : 0.06 seconds Minimum Sampling Parameter : 0.06 seconds Maximum Sampling Parameter : 0.06 seconds Sampling Parameter Interval : 48.0 seconds Minimum Available Sampling Interval : 48.0 seconds Data Set Parameter Name : magnetic field vector Noise Level : 0.006 nT Data Set Parameter Unit : nanotesla Magentic field vector: A derived parameter which combines the 3 orthogonal magnetic field component measurements. Measured Parameters ------------------- Magentic field component: A measured parameter equaling the magnetic field strength (e.g. in nanoteslas) along a particular axis direction. Usually the three orthogonal axis components are measured by three different sensors. Ancillary Data ============== An ancillary data file containing the derived spacecraft magnetic field is provided with this data at a 48 second sample rate. These data provide zero level offsets used in the data processing. S/C field data is provided in spacecraft coordinates. Coordinate System ================= Mean Inertial Heliographic 1950 (HG) Coordinates ------------------------------------------------ COORDINATE_SYSTEM_CENTER_NAME : SUN COORDINATE_SYSTEM_REFERENCE_EPOCH : UNK /* 09-23-1950 */ The Heliographic coordinate system is defined in the reference epoch of 1950. The unit vectors which define the coordinate system are as follows: X points away from the Sun towards the ascending node, in the solar equatorial plane, Z points along the Sun's spin axis, positive above the equatorial plane, and Y completes the right handed set. Position is given in terms of the following: RANGE (R) - The range or R component of the spherical Heliographic coordinate system is the distance from the Sun's position at the reference epoch to the spacecraft measured in AU. LATITUDE (LAT) - The latitude component of the spherical Heliographic coordinate system is the angle between the solar equatorial plane of the reference epoch measured in the plane that contains the solar spin axis of that epoch. LONGITUDE (LONG) - The longitude component of the spherical Heliographic coordinate system is zero in the direction of the ascending node at the reference epoch (X direction) and increases for a body orbiting the Sun as the Earth does. X - The X component of the Heliographic coordinate system points away from the Sun, towards the ascending node, and lies in the solar equatorial plane. Y - The Y vector of the Heliographic coordinate system is formed by the righthanded cross product of the X and Z unit vectors. It lies in the solar equatorial plane and it points away from the Sun, but does not extend in the direction of any particular body. Z - The Z component of the Heliographic coordinat

13) VG2 NEP MAG RESAMP RDR HELIOGRAPHIC COORDINATES 9.6SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/MAG/Neptune/PT9.6S
Start:1989-08-22 00:00:47 Observatory:Voyager 2 Cadence:9.6 seconds
Stop:1989-08-29 00:00:37 Instrument:Triaxial Fluxgate Magnetometer (MAG) Resource:NumericalData
Data Set Overview ================= This data set includes data from the Low Field Magnetometer (LFM) during the inbound Neptune encounter beginning in the solar wind and continuing until the first magnetopause crossing. The magnetometer are given in Heliographic coordinates and the data have been averaged from the 1.92 second averages to a 9.6 second resampled rate. The dataset consists of the following columns: 1) ctime (decimal seconds since 1966-01-01T00:00:00.000), 2) pdstime (ISO standard time format), 3-5) spacecraft clock (m65536,m60,fds-line), 6) magnetometer id (1 = LFM, 2 = HFM), 7), Br (radial component), 8) Bt (tangential component), 9) Bn (normal component), 10) Bmag (magnitude of the average components), 11) avg_Bmag (average of the magnitude of the raw components), 12) Lambda (longitude = tan^-1(Bt/Br)), 13) Delta (latitude = sin^-1(Bn/avg_Bmag) ), 14-16) rms vector (Pythagorean root mean square deviation of the component averages), 17) npts (number of points in average), 18) flag a character string which indicates software or s/c hardware intervention which reduces confidence in the data (NULL flags represent 'good' data). Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : 0.06 seconds Minimum Sampling Parameter : 0.06 seconds Maximum Sampling Parameter : 0.06 seconds Sampling Parameter Interval : 9.6 seconds Minimum Available Sampling Interval : 9.6 seconds Data Set Parameter Name : magnetic field vector Noise Level : 0.006 nT Data Set Parameter Unit : nanotesla Magnetic field vector: A derived parameter which combines the 3 orthogonal magnetic field component measurements. Measured Parameters ------------------- Magentic field component: A measured parameter equaling the magnetic field strength (e.g. in nanoteslas) along a particular axis direction. Usually the three orthogonal axis components are measured by three different sensors. Ancillary Data ============== An ancillary data file containing the derived spacecraft magnetic field is provided with this data at a 48 second sample rate. These data provide zero level offsets used in the data processing. S/C field data is provided in spacecraft coordinates. Coordinate System ================= Mean Inertial Heliographic 1950 (HG) Coordinates ------------------------------------------------ COORDINATE_SYSTEM_CENTER_NAME : SUN COORDINATE_SYSTEM_REFERENCE_EPOCH : UNK /* 09-23-1950 */ The Heliographic coordinate system is defined in the reference epoch of 1950. The unit vectors which define the coordinate system are as follows: X points away from the Sun towards the ascending node, in the solar equatorial plane, Z points along the Sun's spin axis, positive above the equatorial plane, and Y completes the right handed set. Position is given in terms of the following: RANGE (R) - The range or R component of the spherical Heliographic coordinate system is the distance from the Sun's position at the reference epoch to the spacecraft measured in AU. LATITUDE (LAT) - The latitude component of the spherical Heliographic coordinate system is the angle between the solar equatorial plane of the reference epoch measured in the plane that contains the solar spin axis of that epoch. LONGITUDE (LONG) - The longitude component of the spherical Heliographic coordinate system is zero in the direction of the ascending node at the reference epoch (X direction) and increases for a body orbiting the Sun as the Earth does. X - The X component of the Heliographic coordinate system points away from the Sun, towards the ascending node, and lies in the solar equatorial plane. Y - The Y vector of the Heliographic coordinate system is formed by the righthanded cross product of the X and Z unit vectors. It lies in the solar equatorial plane and it points away from the Sun, but does not extend in the direction of any particular body. Z - The Z component of the Heliographic coordinate

14) VG2 NEP PLS DERIVED RDR ION OUTBND MAGSHTH M-MODE 12MIN V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PLS/Neptune/PT12M
Start:1989-08-26 08:36:00 Observatory:Voyager 2 Cadence:12 minutes
Stop:1989-08-30 00:00:00 Instrument:Plasma Spectrometer (PLS) Resource:NumericalData
Data Set Overview ================= This data set gives the best available values for ion densities, temperatures, and velocities near Neptune derived from data obtained by the Voyager 2 plasma experiment. All parameters are obtained by fitting the observed spectra (current as a function of energy) with Maxwellian plasma distributions, using a non-linear least squares fitting routine to find the plasma parameters which, when coupled with the full instrument response, best simulate the data. The PLS instrument measures energy/charge, so composition is not uniquely determined but can be deduced in some cases by the separation of the observed current peaks in energy (assuming the plasma is co-moving). In the upstream solar wind protons are fit to the M-long data since high energy resolution is needed to obtain accurate plasma parameters. In the magnetosheath the ion flux so low that several L-long spectra (3-5) had to be averaged to increase the signal-to-noise ratio to a level at which the data could be reliably fit. These averaged spectra were fit using 2 proton Maxwellians with the same velocity. The values given in the upstream magnetosheath are the total density and the density-weighted temperature. In both the upstream solar wind and magnetosheath full vector velocities, densities and temperatures are derived for each fit component. In the magnetosphere spectra do not contain enough information to obtain full velocity vectors, so flow is assumed to be purely azimuthal. In some cases the azimuthal velocity is a fit parameter, in some cases rigid corotation is assumed. In the 'outer' magnetosphere (L>5) two distinct current peaks appear in the spectra; these are fit assuming a composition of H+ and N+. In the inner magnetosphere the plasma is hot and the composition is ambiguous, although two superimposed Maxwellians are still required to fit the data. These spectra are fit using two compositions, one with H+ and N+ and the second with two H+ components. The N+ composition is preferred by the data provider. All fit values in the magnetosphere come with one sigma errors. It should be noted that no attempt has been made to account for the spacecraft potential, which is probably about -10 V in this region and will effect the density and velocity values. In the outbound magnetosheath and solar wind both moment and fit values are given for velocity, density, and thermal speed. The signal-to-noise ratio in the M-longs is very low, especially near the magnetopause, which can result in the analysis giving incorrect values. The L-long spectra have too low an energy resolution to permit accurate determinations parameters in many regions; in particular the temperature and non-radial velocity components may be inaccurate. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : ion density Noise Level : unk Data Set Parameter Unit : cm**-3 Ion density: A derived parameter equaling the number of ions per unit volume over a specified range of ion energy, energy/charge, or energy/nucleon. Discrimination with regard to mass and or charge state is necessary to obtain this quantity, however, mass and charge state are often assumed due to instrument limitations. Many different forms of ion density are derived. Some are distinguished by their composition (N+, proton, ion, etc.) or their method of derivation (Maxwellian fit, method of moments). In some cases, more than one type of density will be provided in a single dataset. In general, if more than one ion species is analyzed, either by moment or fit, a total density will be provided which is the sum of the ion densities. If a plasma component does not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, in which case the density of each Maxwellian is given. Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : ion temperature Noise Level : unk Data Set Parameter Unit : eV Ion temperature: A derived parameter giving an indication of the mean energy/ion, assuming the shape of the ion energy spectrum to be Maxwellian (i.e. highest entropy shape). Given that the ion energy spectrum is not exactly Maxwellian, the ion temperature can be defined integrally (whereby the mean energy obtained by integrating under the actual ion energy spectrum is set equal to the integral under a Maxwellian, where the temperature is a free

15) VG2 NEP PLS DERIVED RDR ION MAGNETOSPHERE 48SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PLS/Neptune/PT48S
Start:1989-08-24 23:30:00 Observatory:Voyager 2 Cadence:48 seconds
Stop:1989-08-25 08:00:00 Instrument:Plasma Spectrometer (PLS) Resource:NumericalData
Data Set Overview ================= This data set gives the best available values for ion densities, temperatures, and velocities near Neptune derived from data obtained by the Voyager 2 plasma experiment. All parameters are obtained by fitting the observed spectra (current as a function of energy) with Maxwellian plasma distributions, using a non-linear least squares fitting routine to find the plasma parameters which, when coupled with the full instrument response, best simulate the data. The PLS instrument measures energy/charge, so composition is not uniquely determined but can be deduced in some cases by the separation of the observed current peaks in energy (assuming the plasma is co-moving). In the upstream solar wind protons are fit to the M-long data since high energy resolution is needed to obtain accurate plasma parameters. In the magnetosheath the ion flux so low that several L-long spectra (3-5) had to be averaged to increase the signal-to-noise ratio to a level at which the data could be reliably fit. These averaged spectra were fit using 2 proton Maxwellians with the same velocity. The values given in the upstream magnetosheath are the total density and the density-weighted temperature. In both the upstream solar wind and magnetosheath full vector velocities, densities and temperatures are derived for each fit component. In the magnetosphere spectra do not contain enough information to obtain full velocity vectors, so flow is assumed to be purely azimuthal. In some cases the azimuthal velocity is a fit parameter, in some cases rigid corotation is assumed. In the 'outer' magnetosphere (L>5) two distinct current peaks appear in the spectra; these are fit assuming a composition of H+ and N+. In the inner magnetosphere the plasma is hot and the composition is ambiguous, although two superimposed Maxwellians are still required to fit the data. These spectra are fit using two compositions, one with H+ and N+ and the second with two H+ components. The N+ composition is preferred by the data provider. All fit values in the magnetosphere come with one sigma errors. It should be noted that no attempt has been made to account for the spacecraft potential, which is probably about -10 V in this region and will effect the density and velocity values. In the outbound magnetosheath and solar wind both moment and fit values are given for velocity, density, and thermal speed. The signal-to-noise ratio in the M-longs is very low, especially near the magnetopause, which can result in the analysis giving incorrect values. The L-long spectra have too low an energy resolution to permit accurate determinations parameters in many regions; in particular the temperature and non-radial velocity components may be inaccurate. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : ion density Noise Level : unk Data Set Parameter Unit : cm**-3 Ion density: A derived parameter equaling the number of ions per unit volume over a specified range of ion energy, energy/charge, or energy/nucleon. Discrimination with regard to mass and or charge state is necessary to obtain this quantity, however, mass and charge state are often assumed due to instrument limitations. Many different forms of ion density are derived. Some are distinguished by their composition (N+, proton, ion, etc.) or their method of derivation (Maxwellian fit, method of moments). In some cases, more than one type of density will be provided in a single dataset. In general, if more than one ion species is analyzed, either by moment or fit, a total density will be provided which is the sum of the ion densities. If a plasma component does not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, in which case the density of each Maxwellian is given. Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : ion temperature Noise Level : unk Data Set Parameter Unit : eV Ion temperature: A derived parameter giving an indication of the mean energy/ion, assuming the shape of the ion energy spectrum to be Maxwellian (i.e. highest entropy shape). Given that the ion energy spectrum is not exactly Maxwellian, the ion temperature can be defined integrally (whereby the mean energy obtained by integrating under the actual ion energy spectrum is set equal to the integral under a

16) VG2 NEP PLS DERIVED RDR ELECTRON MAGNETOSPHERE 96SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PLS/Neptune/PT96S
Start:1989-08-24 14:38:00 Observatory:Voyager 2 Cadence:96 seconds
Stop:1989-08-25 09:23:00 Instrument:Plasma Spectrometer (PLS) Resource:NumericalData
Data Set Overview ================= The electron spectra are fit using several isotropic Maxwellian distribution functions to find electron parameters. The spacecraft charge may seriously affect the density measurements. The temperature of each component is, however, independent of the spacecraft potential. To obtain the best estimate of the electron density, the encounter period is divided into four regions and four different analysis methods are used. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : electron density Noise Level : unk Data Set Parameter Unit : cm**-3 Electron density: A derived parameter equaling the number of electrons per unit volume over a specified range of electron energy. Different forms of electron density are derived distinguished by method of derivation (Maxwellian fit, method of moments) or by the some selection criteria (i.e., hot electron and cold electron density). In general, if more than one electron component is analyzed, either by moment or fit, a total density will be provided which is the sum of the electron densities. If the electron do not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, in which case the density of each Maxwellian is given. Sampling Parameter Name : time Sampling Parameter Resolution : n/a Minimum Sampling Parameter : unk Maximum Sampling Parameter : unk Sampling Parameter Interval : unk Minimum Available Sampling Interval : unk Data Set Parameter Name : electron temperature Noise Level : unk Data Set Parameter Unit : eV Electron temperature: A derived parameter giving an indication of the mean energy/electron, assuming the shape of the electron energy spectrum to be Maxwellian (i.e. highest entropy shape). Given that the electron energy spectrum is not exactly Maxwellian, the electron temperature can be defined integrally (whereby the mean energy obtained by integrating under the actual electron energy spectrum is set equal to the integral under a Maxwellian, where the temperature is a free parameter for which to solve), or differentially (whereby the slopes of the actually electron energy spectrum at various energies are matched to the slopes of a corresponding Maxwellian). The temperature parameter is often qualified with a range of applicable energies. Temperatures can be angularly anisotropic. If the electrons do not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, each with a separate temperature. Derived Parameters ------------------ Electron Rate: A measured parameter equaling the number of electrons hitting a particle detector per specified accumulation interval. The counted electrons may or may not be discriminated as to their energies (e.g. greater than E1, or between E1 and E2). Electron Current: A measured parameter equaling the rate at which negative charge is collected by a particle detector. The electrons contributing to this current may be restricted by energy. Electrons always have a charge of 1, so this quantity corresponds directly to the electron rate. References ========== Zhang, M., J. D. Richardson, and E. C. Sittler, Jr., Voyager 2 electron observations in the Magnetosphere of Neptune, J. Geophys. Res., in press, 1991. J. W. Belcher, H. S. Bridge, et al., Plasma Observations Near Neptune: Initial Results from Voyager 2, Science, 246, 1478-1483, 1989. Scudder, J. D., E. C. Sittler, Jr. and H. S. Bridge, A survey of the plasma electron environment of Jupiter: a view from Voyager, J. Geophys. Res., 86, 8319-8342, 1981. Sittler, E. C., Jr., K. W. Ogilvie and R. S. Selesnick, Survey of electrons in the Uranian magnetosphere: Voyager 2 observations, J. Geophys. Res., 92, 15,263-15,281, 1987.

17) VG2 NEP PRA EDITED RDR HIGH RATE 60MS V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PRA/Neptune/PT0.60S
Start:1989-05-25 06:58:32 Observatory:Voyager 2 Cadence:0.60 seconds
Stop:1989-09-27 17:52:43 Instrument:Voyager 2 Planetary Radio Astronomy (PRA) experiment Resource:NumericalData
This data set (VG2-N-PRA-2-RDR-HIGHRATE-60MS-V1.0) contains data acquired by the Voyager-2 Planetary Radio Astronomy (PRA) instrument during the Neptune encounter. Since the PRA instrument is able to observe planetary phenomenon at much larger ranges than other fields and particles experiments, thus the PRA data cover a variable and longer encounter period. PRA lowband data provided here cover the entire Neptune Encounter Phase (1989-05-25 to 1989-09-27). Each file within the dataset represents a single PRA high rate frame, of duration 48 seconds. Each file contains a 28 octet header, followed by 1280000 octets of data. The header format is described as below: -------------------------------------------------------------------- Length (bytes) Name Contents -------------------------------------------------------------------- 2 Year Year A.D. 2 Day Day of year (1 Jan == 1) 1 Hour Hour of day (midnight == 0) 1 Minute Minute of hour (o'clock = 0) 1 Second Second of Minute (exact minute == 0) 1 Spacecraft 1 == V1, 2 == V2 2 Integral FDS Integer part of FDS count 1 Fractional FDS Fractional part of FDS count 4 Freq. 1 Frequency of 1st channel (Hz) 4 Freq. 2 Frequency of 2nd channel (Hz) 4 Freq. 3 Frequency of 3rd channel (Hz) 4 Freq. 4 Frequency of 4th channel (Hz) 1 Bandwidth Bandwidth (kHz) -------------------------------------------------------------------- where all values are unsigned, and multi-octet values are presented with the most significant byte first. The data are 16 bit numbers, most significant byte first, with 0 indicating unavailable data. The data are presented as a single stream of 16 bit numbers. The frame is logically divided into lines (although there is no indication of the lines within the file). This terminology comes from the fact that in this high rate mode, the PRA data are treated exactly as if they were imaging data, and a 48 second image comprises 800 horizontal scan lines. Similarly, there are 800 logical lines within a PRA frame. Each line comprises 800 values, representing 400 data pairs. In the high rate mode, the PRA measures the flux at two frequencies _simultaneously_ and returns these two data sequentially. A sample pair is acquired every (actually every 138.88... microseconds), through an RC filter with a 100 microsecond time constant. A single line comprises 60 milliseconds of data. Lines are NOT contiguous in time. There is a 4444.44... microsecond gap between the ending of one line and the start of the succeeding line. The PRA samples a frequency pair in this manner for 24 seconds. It then has the option of switching to a second pair for the final 24 seconds. These frequencies are designated Freq. 1 through Freq. 4 in the header. The data are presented such that the higher of the relevant frequency pair is presented first.

18) VG2 NEP PRA RESAMPLED SUMMARY BROWSE 48SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PRA/Neptune/PT48S
Start:1989-08-18 00:00:00 Observatory:Voyager 2 Cadence:48 seconds
Stop:1989-09-06 23:59:59 Instrument:Voyager 2 Planetary Radio Astronomy (PRA) experiment Resource:NumericalData
Data Set Overview ================= This dataset consists of edited browse data derived from an original dataset obtained from the Voyager 2 Planetary Radio Astronomy (PRA) instrument in the vicinity of Neptune. Data are provided for 70 instrument channels covering the range from 1.2 kHz to 1326 kHz in uniform 19.2 kHz steps, each 1 kHz wide. Data are included for the period 1989:0:0:0 through 1989:23:59:59. Parameters ========== Sampling Parameter Name : time Sampling Parameter Resolution : 0.001 seconds Minimum Sampling Parameter : N/A Maximum Sampling Parameter : N/A Sampling Parameter Interval : 48.0 seconds Minimum Available Sampling Interval : 12.0 seconds Data Set Parameter Name : radio wave spectrum Noise Level : 2400 mB Data Set Parameter Unit : millibel Radio wave spectrum: A set of derived parameters consisting of power fluxes at various contiguous frequencies over a range of frequencies. The MKS units are: (hertz.meter**2). Processing ========== In order to produce this dataset from the original raw PRA data, several steps have been taken: 1. The PRA operates in a variety of modes; data from modes in which the receiver does not scan rapidly through its frequency range have been removed; 2. The data have been calibrated as best we know how; 3. The data have been split into Left Hand Circular (LHC) and Right Hand Circular (RHC) components; 4. The data have been binned into 48-second intervals. Thus, values at a given channel are separated in time by an increment of 48 seconds; each 48-second time interval has associated with it a value for LHC polarization and one for RHC polarization. During data gaps, the entire record is absent from the dataset; that is, missing records have not been zero-filled or otherwise marked. Bad data within a record is indicated by the value zero, which cannot otherwise occur. Each datum is returned as a 16-bit quantity; it represents the mean power received in the given channel at the specified time and polarization. The returned quantity is the value in mB about a reference flux density. The value of 0 mB represents a voltage of 1 microvolt across the front end of the receiver. To convert a returned quantity to flux, use the formula: flux = 7.0x10^(-22)x10^(mB/1000) W m-2 Hz-1

19) maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PRA/Neptune/PT6S
Start:1970-01-01 00:00:00 Observatory:Voyager 2 Cadence:6 seconds
Stop:1986-09-01 00:00:00 Instrument:Voyager 2 Planetary Radio Astronomy (PRA) experiment Resource:NumericalData
Voyager 2 PRA lowband 6 second data recorded at Neptune.

20) VG2 NEP PWS RAW EXPERIMENT WAVEFORM 60MS V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PWS/Neptune/PT0.60S
Start:1989-06-06 14:16:56 Observatory:Voyager 2 Cadence:0.60 seconds
Stop:1989-09-27 17:52:43 Instrument:Plasma Wave System (PWS) Resource:NumericalData
Data Set Overview ================= This data set consists of electric field waveform samples from the Voyager 2 Plasma Wave Receiver waveform receiver obtained during the Neptune encounter. The waveforms are collections of 4-bit samples of the electric field measured by the dipole electric antenna at a rate of 28,800 samples per second. 1600 samples are collected in 55.56 msec followed by a 4.44-msec gap. Each 60-msec interval constitutes a line of waveform samples. The data set includes about 271 frames of waveform samples consisting of up to 800 lines, each. The telemetry format for the waveform data is identical to that for images, hence the use of line and frame as constructs in describing the form of the data. The waveform is sampled through a bandpass filter with a passband of 40 Hz to 12 kHz. The 4-bit samples provide sixteen digital values of the electric field with a linear amplitude scale, but the amplitude scale is arbitrary because of the automatic gain control used in the waveform receiver. The instantaneous dynamic range afforded by the 4 bit samples is about 23 db, but the automatic gain control allows the dominant signal in the passband to be set at the optimum level to fit within the instantaneous dynamic range. With the gain control, the overall dynamic range of the waveform receiver is about 100 db. The automatic gain control gain setting is not returned to the ground, hence, there is no absolute calibration for the data. However, by comparing the waveform spectrum derived by Fourier transforming the waveform to the spectrum provided by the spectrum analyzer data, an absolute calibration may be obtained in most cases. The data may be plotted in raw form to show the actual waveform; this is useful for studying events such as dust impacts on the spacecraft. But the normal method of analyzing the waveform data is by Fourier transforming the samples from each line to arrive at an amplitude versus frequency spectrum. By stacking the spectra side-by-side in time order, a frequency- time spectrogram can be produced. Additional information about this dataset and the instrument which produced it can be found elsewhere in this catalog. An overview of the data in this data set can be found in Gurnett et al. [1989] and a complete instrument description can be found in Scarf and Gurnett [1977]. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : time Sampling Parameter Resolution : 0.000034722 seconds Minimum Sampling Parameter : n/a Maximum Sampling Parameter : n/a Sampling Parameter Interval : 0.000034722 seconds Minimum Available Sampling Interval : 0.000034722 seconds Data Set Parameter Name : plasma wave waveform Noise Level : 0.000005 Data Set Parameter Unit : volt/meter (Data not absolutely calibrated) Plasma wave waveform: A plasma wave waveform is a time series of measurements of the electric or magnetic field component of the wave spectrum taken through a broadband filter. The temporal sample rate is normally such that samples are made at more than twice the analysis filter bandwidth. A typical waveform will consist of the order of 1000 contiguous samples of between 4 and 12 bits each. For a 10-kHz analysis bandwidth, the sample rate would normally be approximately 25 kHz or 25,000 samples/second. Once received, the waveforms are typically Fourier transformed in order to provide an amplitude versus frequency spectrum across the analysis bandwidth. The sample rate, then, is required to be at least a factor of two greater than the filter bandwidth in order to avoid aliasing in the transformed spectrum. The spectra can be stacked side-by-side in time to build a frequency-time spectrogram (that is, amplitude as a function of time and frequency) in order to identify the temporal and spectral variations in the wave spectrum. Alternately, the untransformed time series can be used to study the details of the waveform. This has been useful for measuring small-scale structures in the plasma and for identifying the signature of micron-sized dust impact on the spacecraft. Measured Parameters ------------------- Electric field component: A measured parameter equaling the electric field strength (e.g. in milli-volts per meter) along a particular axis direction. Wave magnetic field intensity: A measured parameter equaling the magnetic field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Wave electric field intensity: A measured parameter equaling the electric field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Processing ========== The data files in this data set were created using the 'CDREF'

21) VG2 NEP PWS RESAMPLED SUMMARY SPECTRUM ANALYZER 48SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PWS/Neptune/PT48S
Start:1989-08-21 00:00:00 Observatory:Voyager 2 Cadence:48 seconds
Stop:1989-08-31 00:00:00 Instrument:Plasma Wave System (PWS) Resource:NumericalData
Data Set Overview ================= This data set consists of 48-second calibrated, averaged wave electric field intensities from the Voyager 2 Plasma Wave Receiver spectrum analyzer obtained in the vicinity of the Neptunian magnetosphere. For each 48-second interval, a geometric average field strength is determined for each of the 16 spectrum analyzer channels whose center frequencies range from 10 Hertz to 56.2 kiloHertz and which are logarithmically spaced in frequency, four channels per decade. The time associated with each set of averages is the beginning of the averaging interval. Averages are stored in units of volt/meter. During data gaps where complete 48-second intervals are missing, no entries exist in the file, that is, the gaps are not zero-filled or tagged in any other way. Additional information about this dataset and the instrument which produced it can be found elsewhere in this catalog. An overview of the data in this data set can be found in Gurnett et al. [1989] and a complete instrument description can be found in Scarf and Gurnett [1977]. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : TIME Sampling Parameter Resolution : 48.0 seconds Minimum Sampling Parameter : N/A (1977-08-20T15:53:00Z) Maximum Sampling Parameter : N/A Sampling Parameter Interval : 48.0 seconds Minimum Available Sampling Interval : 4.0 seconds Data Set Parameter Name : plasma wave spectrum Noise Level : 0.000005 V/m Data Set Parameter Unit : volts/meter Plasma wave spectrum: A set of derived parameters consisting of wave electric field intensities or electric field spectral densities at various contiguous frequencies over a range of frequencies. The MKS units are: volts/meter or volts**2/(hertz.meter**2), respectively. Measured Parameters ------------------- Electric field component: A measured parameter equaling the electric field strength (e.g. in milli-Volts per meter) along a particular axis direction. Wave magnetic field intensity: A measured parameter equaling the magnetic field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Wave electric field intensity: A measured parameter equaling the electric field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Processing ========== The data files in this data set were created from the SA 4 second data set (VG2-N-PWS-2-EDR-SA-4SEC-V1.0), using the 'V2U48' software. V2U48 ----- Node ID : PPI-IOWA Software Release Date : 1988-08-01 Cognizant Full Name : MR. LARRY J. GRANROTH V2U48 is a specialized, hard-coded routine to process a specific interval of Voyager 2 Plasma Wave Spectrometer (PWS) spectrum analyzer data around Uranus encounter. Input is from MSF or CD data sets produced and stored at the University of Iowa, and output is to ASCII text files which are compatible with PDS data loading procedures. These files contain information corresponding to the VG2-N-PWS-4-SUMM-SA-48SEC-V1.0 and VG2-U-PWS-4-SUMM-SA-48SEC data set. NOTE: SOFTWARE IS NOT AVAILABLE FOR PUBLIC USE.

22) VG2 NEP PWS EDITED RDR UNCALIB SPECTRUM ANALYZER 4SEC V1.0 maxmize
Resource ID:spase://VMO/NumericalData/Voyager2/PWS/Neptune/PT4S
Start:1989-08-21 00:00:00 Observatory:Voyager 2 Cadence:4 seconds
Stop:1989-08-31 00:00:00 Instrument:Plasma Wave System (PWS) Resource:NumericalData
Data Set Overview ================= This data set consists of 4-second edited, wave electric field intensities from the Voyager 2 Plasma Wave Receiver (PWS) spectrum analyzer obtained in the vicinity of the Neptunian magnetosphere. For each 4-second interval, a field strength is determined for each of the 16 spectrum analyzer channels whose center frequencies range from 10 Hertz to 56.2 kiloHertz and which are logarithmically spaced in frequency, four channels per decade. The time associated with each set of intensities (16 channels) is the time of the beginning of the scan. During data gaps where complete 4-second spectra are missing, no entries exist in the file, that is, the gaps are not zero-filled or tagged in any other way. When one or more channels are missing within a scan, the missing measurements are zero-filled. Data are edited but not calibrated. The data numbers in this data set can be plotted in raw form for event searches and simple trend analysis since they are roughly proportional to the log of the electric field strength. Calibration procedures and tables are provided for use with this data set; the use of these is described below. Parameters ========== Derived Parameters ------------------ Sampling Parameter Name : TIME Sampling Parameter Resolution : 4.0 seconds Minimum Sampling Parameter : N/A Maximum Sampling Parameter : N/A Sampling Parameter Interval : 4.0 seconds Minimum Available Sampling Interval : 4.0 seconds Data Set Parameter Name : plasma wave spectrum Noise Level : 0.000005 V/m Data Set Parameter Unit : volts/meter Plasma wave spectrum: A set of derived parameters consisting of wave electric field intensities or electric field spectral densities at various contiguous frequencies over a range of frequencies. The MKS units are: volts/meter or volts**2/(hertz.meter**2), respectively. Measured Parameters ------------------- Electric field component: A measured parameter equaling the electric field strength (e.g. in milli-volts per meter) along a particular axis direction. Wave magnetic field intensity: A measured parameter equaling the magnetic field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Wave electric field intensity: A measured parameter equaling the electric field strength in a specific frequency passband (in MKS unit: volts/meter) measured in a single sensor or antenna. Processing ========== The data files in this data set were created using the 'CDMAKE' software. CDMAKE ------ Node ID : PPI-IOWA Software Release Date : 1988-08-01 Cognizant Full Name : MR. LARRY J. GRANROTH CDMAKE is primarily a data format translation routine which is used to convert Voyager Plasma Wave Spectrometer (PWS) MSF tape files to CD files. The MSF, or Master Science Files, are produced at the University of Iowa as the primary, ordered, full-information PWS spectrum analyzer data set. The CD files contain uncalibrated, full-resolution PWS data with minimal ancillary data in a simplified format which may be used in CDROM production. NOTE: SOFTWARE IS NOT AVAILABLE FOR PUBLIC USE. Use of Voyager PWS Calibration Tables ------------------------------------- The Voyager PWS calibration tables are given in two plain ASCII text files named VG1PWSCL.TAB and VG2PWSCL.TAB (for Voyagers-1 and -2, respectively). These provide information to convert the uncalibrated `data number' output of the PWS 16-channel spectrum analyzer to calibrated antenna voltages for each frequency channel. These calibration files are always provided with the dataset when the data are extracted from PDS by a user. Following is a brief description of these files and a tutorial in their application. The first column lists an uncalibrated data number followed by the corresponding value in calibrated volts for each of the 16 frequency channels of the PWS spectrum analyzer. Each line contains calibrations for successive data number values ranging from 0 through 255. (Data number 0 actually represents the lack of data since the baseline noise values for each channel are all above that.)

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