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1) | Polar Plasma Wave Instrument, High Frequency Waveform Receiver, 25kHz bandwidth interferometry fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/HFWR.25kHz.Interferometry.PT0.000014S | ||||||||||||||||||

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PWI>Plasma Wave Instrument Reference: Gurnett, D.A. et al, The Polar Plasma Wave Instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. donald-gurnett@uiowa.edu An FFT on 1024 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Coordinate system used: antenna coordinate system, where the u-axis is offset by -45 degrees from the spacecraft x-axis, the v-axis is offset by -45 degrees from the spacecraft y-axis, and the z-axis is identical to the spacecraft z-axis. Effective bandwidth is 1.5*delta_f, where delta_f depends on the size of the FFT used to convert to the frequency domain, and delta_t. These data come in snapshots of 190902 points distributed among 2 to 6 channels every 9.2 seconds, where the duration of the snapshot is 0.045 seconds. Since Epoch time is in milliseconds, the times for the data points will not be unique unless the Delta_T in milliseconds is added to the Epoch time for the snapshot. The unattenuated frequency range for this file type is 20Hz to 25000Hz. The cadence value given here is computed from the inverse of the sampling rate (71.43 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

2) | Polar Plasma Wave Instrument, High Frequency Waveform Receiver, 25kHz bandwidth, 6-channel fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/HFWR.25kHz.PT0.000014S | ||||||||||||||||||

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PWI>Plasma Wave Instrument Reference: Gurnett, D.A. et al, The Polar Plasma Wave Instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. donald-gurnett@uiowa.edu An FFT on 1024 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Coordinate system used: local magnetic field-aligned, a spacecraft centered coordinate system where Z is parallel to the local B-field determined from Polar MFE, X points outward and lies in the plane defined by the Z-axis and the radial vector from the earth to the spacecraft, and Y completes a right-handed system and points eastward. The X- and Z-axes are contained in the north-south plane. Effective bandwidth is 1.5*delta_f, where delta_f depends on the size of the FFT used to convert to the frequency domain, and delta_t. These data come in snapshots of 31816 points per channel, every 9.2 seconds, where the duration of each snapshot is 0.045 seconds. The time for individual samples is the epoch time of the snapshot incremented by delta_t in milliseconds for each successive sample. That is: sample_time = epoch_time + sample_offset * delta_t The data in this file will be in sets of 31744 (31*1024) points per channel because the FFT size does not come out even within the number of points per snapshot. To obtain the time for each point in the snapshot, increment each Epoch time after the first with Delta_T (in ms). The unattenuated frequency range for this file type is 20Hz to 25000Hz. The cadence value given here is computed from the inverse of the sampling rate (71.43 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

3) | Polar Plasma Wave Instrument, Low Frequency Waveform Receiver, ~0.01 sec resolution fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/LFWR.PT0.01S | ||||||||||||||||||

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The Low-Frequency Waveform Receiver (LFWR) is designed to provide an extension of the High Frequency Waveform Receiver into the frequency range below 25 Hz. The LFWR consists of six parallel low-pass filters connected to the three orthogonal electric field sensors and to the triaxial search coils. The input signals are band limited to a frequency range from 0.1 to 25 Hz and are sam- pled by a 12-bit analog-to-digital converter. The six LFWR channels are sampled simultaneously at a rate of 100 samples s-1. The dynamic range of the LFWRis approximately 72 dB with fixed gain. An FFT on 256 or 464 values, depending on the snapshot size, was used in calibrating the data; i.e., perform FFT, calibrate andin frequency domain, perform inverse FFT to get calibrated time series. Coordinate System Used: local magnetic field-aligned, a spacecraft centered coordinate system where Z is parallel to the local B-field determined from Polar MFE, X points outward and lies in the plane defined by the Z-axis and the radial vector from the earth to the spacecraft, and Y completes a right-handed system and points eastward. The X- and Z-axes are contained in the north-south plane. The three orthogonal magnetic field components are given in units of nT/Sec rather than nT because the response of the searchcoils across the passband is not flat. In order to obtain units of nT, the data would need to be digitally filtered to the frequency of interest and then integrated over time. Integrating over the entire passband could possibly destroy the resolution of the higher frequency components since the low frequency noise, if present, will dominate. Data are bandpass filtered. The valid range of data in the frequency domain is from 0.5 to 22.5 Hz. Reference:..Gurnett, D.A. et al, The Polar plasma wave instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. |

4) | Polar Plasma Wave Instrument, High Frequency Waveform Receiver, 16 kHz, Time Domain Fields. | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/LHFWR.16kHz.Interferometry.PT0.000028S | ||||||||||||||||||

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The unattenuated frequency range for this file type is 20Hz to 16000Hz. The cadence value given here is computed from the inverse of the sampling rate (35.71 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

5) | Polar Plasma Wave Instrument, High Frequency Waveform Receiver, 16 kHz bandwidth, 6-channel Fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/LHFWR.16kHz.PT0.000028S | ||||||||||||||||||

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PWI>Plasma Wave Instrument Reference: Gurnett, D.A. et al, The Polar Plasma Wave Instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. donald-gurnett@uiowa.edu An FFT on 1024 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Coordinate system used: local magnetic field-aligned, a spacecraft centered coordinate system where Z is parallel to the local B-field determined from Polar MFE, X points outward and lies in the plane defined by the Z-axis and the radial vector from the earth to the spacecraft, and Y completes a right-handed system and points eastward. The X- and Z-axes are contained in the north-south plane. Effective bandwidth is 1.5*delta_f, where delta_f depends on the size of the FFT used to convert to the frequency domain, and delta_t. These data come in snapshots of 31816 points per channel, every 9.2 seconds, where the duration of each snapshot is 0.045 seconds. The time for individual samples is the epoch time of the snapshot incremented by delta_t in milliseconds for each successive sample. That is: sample_time = epoch_time + sample_offset * delta_t The data in this file will be in sets of 31744 (31*1024) points per channel because the FFT size does not come out even within the number of points per snapshot. To obtain the time for each point in the snapshot, increment each Epoch time after the first with Delta_T (in ms). The unattenuated frequency range for this file type is 20Hz to 16000Hz. The cadence value given here is computed from the inverse of the sampling rate (35.71 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

6) | Polar Plasma Wave Instrument, High Frequency Waveform Receiver, 2 kHz, Time Domain Fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/LHFWR.2kHz.PT0.000224S | ||||||||||||||||||

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An FFT on 2048 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Data are lowpass filtered so that the data are valid only up to 2 kHz. The three orthogonal magnetic field components are given in units of nT/Sec rather than nT because the response of the searchcoils across the passband is not flat. In order to obtain units of nT, the data would need to be digitally filtered to the frequency of interest and then integrated over time. Integrating over the entire passband could possibly destroy the resolution of the higher frequency components since the low frequency noise, if present, will dominate. Effective Bandwidth is 1.5*delta_f, where delta_f depends on the size of the FFT used to convert to the frequency domain, and delta_t. The unattenuated frequency range for this file type is 20Hz to 2000Hz. The cadence value given here is computed from the inverse of the sampling rate (4.46 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

7) | Polar PWI MCA Survey Spectrograms | |||||||||||||||||
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Resource ID:spase://VWO/DisplayData/POLAR/PWI/MCA.DS.P1D | ||||||||||||||||||

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The Polar PWI Multichannel Analyzer (MCA) collected data from March 1996 to September 1997. The MCA data has very good time resolution (~1 s) but relatively poor frequency resolution. An electric field measurement covers 5.6 Hz to 311 kHz in 20 channels logarithmically spaced. The magnetic field measurements cover a range from 5.6 Hz to 10 kHz in 14 channels logarithmically spaced. Each file consists of two plots. Each plot contains the power spectral density (color scale) of received signal (upper plot: electric (V^2 m^-2 Hz^-1), lower plot: magnetic (nT^2 Hz^-1) ) as a function of operating frequency (in a logarithmic scale on vertical axis) and time (horizontal axis). At the top of each plot is a title indicating the Instrument, Receiver and Antenna used along with the time span for the spectrogram. Overlaid on each image is a trace of the electron gyrofrequency. Beneath the time labels on the horizontal axis of the lower plot are ephemeris data: position of the spacecraft in radial distance (Earth radii), geomagnetic latitude, magnetic local time, and McIlwain L-shell. Overlaid on each image is a trace of the electron gyrofrequency. Reference: Gurnett, D.A. et al, The Polar plasma wave instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. |

8) | Polar Plasma Wave Instrument, Multichannel Analyzer - 1.3 sec resolution fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/MCA.PT1.3S | ||||||||||||||||||

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The PO_H0_PWI Multichannel Analyzer (MCA) CDF files provide good time resolution with relatively poor frequency resolution. An electric field measurement covers 5.6 Hz to 311 kHz in 20 channels logarithmically spaced. The magnetic field measurements cover a range from 5.6 Hz to 10 kHz in 14 channels logarithmically spaced. Reference: Gurnett, D.A. et al, The Polar plasma wave instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. Note: The electron cyclotron frequencies are derived from the following: Fce = 0.028 kHz*B, where B is the magnitude of the ambient magnetic field measured in nT. |

9) | Polar PWI SFR-A Daily Dynamic Spectrograms | |||||||||||||||||
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Resource ID:spase://VWO/DisplayData/POLAR/PWI/SFR.A.DS.P1D | ||||||||||||||||||

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The Polar Sweep Frequency Receiver-A (SFR-A) made use of either the Eu (130 m, spin-plane) or Ez (14 m, spin axis) two-sphere electric dipole antennas. Between March 25, 1996 and May 26, 1996, the Eu antenna was the default antenna, from May 27, 1996 through February 9, 1997 the Ez antenna was used and from February 10, 1997 until September 17, 1997 the SFR-A returned to using the Eu antenna. The SFR-A receiver spanned the frequency range from 26 Hz to 808 kHz in 5 bands: 26-200 Hz, 0.2 - 1.6 kHz, 1.7 - 12.6 kHz, 13-100 kHz, 100-808 kHz. Each image is a daily plot of the power spectral density (V^2 m^-2 Hz^-1) of received signal (color scale) as a function of operating frequency (in a logarithmic scale on vertical axis) and time (horizontal axis). At the top of each plot is a title indicating the Instrument, Receiver and Antenna used followed by the time span for the spectrogram. Beneath the time labels on the horizontal axis are ephemeris data: position of the spacecraft in radial distance (Earth radii), geomagnetic latitude, magnetic local time, and McIlwain L-shell. Overlaid on each image is a trace of the electron gyrofrequency. |

10) | Polar Plasma Wave Instrument, Sweep Frequency Receivers A and B - 2 sec resolution fields | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/SFR.AB.PT2S | ||||||||||||||||||

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The PO_H1_PWI CDF files contain spectral densities of magnetic and electric field measurements from the Sweep Frequency Receiver-A and B. These files also contain correlation, electron cyclotron frequency, upper hybrid frequency and electron number density data. A full frequency sweep for the SFR takes about 33 seconds. From about 12.5 kHz to 800 kHz a full frequency spectrum can be obtained every 2.4 sec in the log mode. There are 224 SFR frequency bands, logarithmically spaced. When SFR_MODE is Linear, the 448 linear frequency bands are mapped to 224 logarithmic bands. The Polar Sweep Frequency Receiver-A (SFR-A) made use of either the Eu (130 m, spin-plane) or Ez (14 m, spin axis) two-sphere electric dipole antennas. Between March 25, 1996 and May 26, 1996, the Eu antenna was the default antenna, from May 27, 1996 through February 9, 1997 the Ez antenna was used and from February 10, 1997 until September 17, 1997 the SFR-A returned to using the Eu antenna. The SFR-A receiver spanned the frequency range from 26 Hz to 808 kHz in 5 bands: 26-200 Hz, 0.2 - 1.6 kHz, 1.7 - 12.6 kHz, 13-100 kHz, 100-808 kHz. The Polar PWI Sweep Frequency Receiver-B (SFR-B) collected data from March 1996 to September 1997. The SFR-B used the magnetic loop antenna (mounted on a 6m boom and oriented parallel to the Eu antenna). The SFR-B receiver spanned the frequency range from 26 Hz to 808 kHz in 5 bands: 26-200 Hz, 0.2 - 1.6 kHz, 1.7 - 12.6 kHz, 13-100 kHz, 100-808 kHz. |

11) | Polar PWI SFR-B Daily Dynamic Spectrograms | |||||||||||||||||
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Resource ID:spase://VWO/DisplayData/POLAR/PWI/SFR.B.DS.P1D | ||||||||||||||||||

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The Polar PWI Sweep Frequency Receiver-B (SFR-B) collected data from March 1996 to September 1997. The SFR-B used the magnetic loop antenna (mounted on a 6m boom and oriented parallel to the Eu antenna). The SFR-B receiver spanned the frequency range from 26 Hz to 808 kHz in 5 bands: 26-200 Hz, 0.2 - 1.6 kHz, 1.7 - 12.6 kHz, 13-100 kHz, 100-808 kHz. Each image is a daily plot of the power spectral density (nT^2 Hz^-1) of received signal (color scale) as a function of operating frequency (in a logarithmic scale on vertical axis) and time (horizontal axis). At the top of each plot is a title indicating the Instrument, Receiver and Antenna used followed by the time span for the spectrogram. Beneath the time labels on the horizontal axis are ephemeris data: position of the spacecraft in radial distance (Earth radii), geomagnetic latitude, magnetic local time, and McIlwain L-shell. Overlaid on each image is a trace of the electron gyrofrequency. |

12) | Polar Plasma Wave Instrument, Wideband Receiver (WBR) 4.016 microsecond resolution | |||||||||||||||||
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Resource ID:spase://VWO/NumericalData/POLAR/PWI/WBR.PT0.000004016S | ||||||||||||||||||

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PWI>Plasma Wave Instrument Reference: Gurnett, D.A. et al, The Polar Plasma Wave Instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. donald-gurnett@uiowa.edu An FFT on 1992 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Coordinate system used: antenna coordinate system, where the u-axis is offset by -45 degrees from the spacecraft x-axis, the v-axis is offset by -45 degrees from the spacecraft y-axis, and the z-axis is identical to the spacecraft z-axis. The effective noise bandwidth is the data sampling frequency divided by the size of the FFT (number of input samples) multiplied by 1.5 to to correct for the effects of a Hanning window applied to the time- domain samples. Hence, the effective noise bandwidth is 1.5 * delta_f. These data come in snapshots of 1992 or 3984 points every 0.064 seconds. Duration of a snapshot is less when the instrument is in duty cycle modes. Since Epoch time is in milliseconds, the times for the data points will not be unique unless the fmsec (fraction of milliseconds) is appended to the Epoch0 time for that point. The frequency filters used for the wideband receiver have a range that limits the calibration. The following table specifies the range of frequencies for which the calibration is certified. Outside this range the amplitude values may be in error and should not be used. +------------------------------------------------+ |Translation| Filter| | Freq Range| |------------------------------------------------| | 0 kHz| 90 kHz| | 7.5 kHz- 90.0 kHz| | 125 kHz| 90 kHz| | 131.9 kHz-214.8 kHz| | 250 kHz| 90 kHz| | 254.3 kHz-341.2 kHz| | 500 kHz| 90 kHz| | 504.79 kHz-591.1 kHz| | 0 kHz| 10 kHz| | 0.035 kHz- 11.64 kHz| | 0 kHz| 22 kHz| | 0.065 kHz- 21.59 kHz| | 0 kHz| 1-3 kHz| | 1.0 kHz- 3.0 kHz| | 0 kHz| 3-6 kHz| | 3.0 kHz- 6.0 kHz| +------------------------------------------------+ The cadence value given here is computed from the inverse of the sampling rate (249 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html |

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