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.
Version:2.6.0
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.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Donald.A.Gurnett | |||
| 2. | GeneralContact | spase://SMWG/Person/J.Douglas.Menietti | |||
| 3. | MetadataContact | spase://SMWG/Person/Lee.Frost.Bargatze |
A Polar PWI page is maintained at the University of Iowa with descriptions of interpretation issues, user's guides, data availability tables, a form for creating summary plots and access to pregenerated dynamic spectrograms.
FTP access to repository of Polar PWI MCA CDFs at NASA CDAWeb. Name of the data resource: PO_H2_PWI
In CDF via HTTP from SPDF
Repository of Polar PWI data with subset, plot, and list functionalities from NASA CDAWeb, accessible via web interface. Name of the data resource: PO_H2_PWI.
Web Service to this product using the HAPI interface.
Time
Time, time between points
Number of snapshots in this file
Data Quality 0 = OK, 1 = poor
LFWR Elec. Field, Antenna Ex (perp and outward in Local-Field-Aligned/LFA coords)
LFWR Elec. Field, Antenna Ey (perp and eastward in Local-Field-Aligned/LFA coords)
LFWR Elec. Field, Antenna Ez (parallel in Local-Field-Aligned/LFA coords)
LFWR Mag. Field, Antenna Bx (perp and outward in Local-Field-Aligned/LFA coords)
LFWR Mag. Field, Antenna By (perp and eastward in Local-Field-Aligned/LFA coords)
LFWR Mag. Field, Antenna Bz (parallel in Local-Field-Aligned/LFA coords)
Time, begin time of LFWR snapshot
Size of FFT used in Calibration of snapshot beginning at Epoch0