DOI: 10.24400/802406/m5h0-wfvq
title: PARKER SOLAR PROBE FIELDS Level 2 DFB Search Coil Magnetometer (SCM) Waveform (CDF)

description: This data set contains the PARKER SOLAR PROBE FIELDS Level 2 Search-coil (SCM) waveform data from the low-frequency (LF) antennas. The waveforms consist of 3 components of the magnetic field, expressed in sensor coordinates (Bu, Bv, Bw) and in spacecraft coordinates (Bx, By, Bz). For the description of the coordinate systems, see the description of the SCM. Time (epoch) is in TT2000 format and corresponds to nanoseconds since 1 Jan 2000 12:00:00 with leap seconds included. The SCM operates mostly during encounter phases (i.e. during a period of typically two weeks around each perihelion). The time resolution for the waveforms is 150000 Hz / 2^N. In general, N=9, which corresponds to 292.969 samples per second. During encounters 6 and 7 the sampling rate occasionally went as high as 2343.8 Hz. The LF antennas of the SCM have a low-frequency cutoff at 3 Hz and an upper frequency rolloff at 10 kHz. Waveforms therefore should not be interpreted below 3 Hz. The waveforms of the Search-Coil Magnetometer (SCM) [Jannet et al., 2021] are primarily registered by the Digital Fields Board (DFB) instrument [Malaspina et al., 2016], which is part of the FIELDS suite [Bale et al., 2016]. DFB provides waveform data for various FIELDS sensors. The Level 2 data products are calibrated for : - DFB in-band gain, - DFB analog filter gain/phase response, - DFB digital filter phase (*not* gain) response, and the search coil preamplifier gain/phase response (when applicable). Calibrations for the DFB digital filter gain response have *not* been implemented, but the required convolution kernel is provided in the cdf datafiles. The reason for not including this gain response in the L2 data is because this can introduce unphysical enhancements of spectral power at high frequencies when the uncorrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. All magnetic fields are expressed in nT. Calculation of the PSP-Sun distance for the selection criterion (see Filter tab) is realized each day at 00:00. SCM anomaly: From 3 March 2019 onwards the LF Bu antenna lost its sensitivity below 1 kHz. This problem occurs whenever the sensor is cold, i.e. at perihelion. At the same time, the sensitivity of the LF Bu antenna to periodic spikes associated with heater cycling has increased by two orders of magnitude. The data are correct for encounter 1 (October-November 2018) only. For subsequent encounters, only Bv and Bw should be used, or Bu above 1 kHz. References: FIELDS website: https://fields.ssl.berkeley.edu/ Bale, S. et al. (2016), The FIELDS Instrument Suite for Solar Probe Plus. Measuring the Coronal Plasma and Magnetic Field, Plasma Waves and Turbulence, and Radio Signatures of Solar Transients, Space Science Reviews, Volume 204, Issue 1-4, pp.49-82, doi:10.1007/s11214-016-0244-5 Malaspina, D.M., Ergun, R.E., Bolton, M. et al. (2016), The Digital Fields Board for the FIELDS instrument suite on the Solar Probe Plus mission: Analog and digital signal processing, Journal of Geophysical Research: Space Physics, 121, 5088-5096, doi: 10.1002/2016JA022344 Jannet, G., Dudok de Wit, T., Krasnoselskikh, V. et al. (2021), Measurement of magnetic field fluctuations in the parker solar probe and solar orbiter missions, Journal of Geophysical Research: Space Physics, 126, e2020JA028543 doi: 10.1029/2020JA028543