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 1.5delta_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 (311024) 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