PSP FIELDS Digital Fields Board (DFB), XXX ⨯ YYY cross spectra data:
The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].
DFB AC cross spectra data for a pair of input channels consist of:
where all as a function of frequency and time. The last two terms are describedcoherence and phase are defined in [3].
These cross spectra are averaged in both frequency and time as described in [3]. The cross spectra have either 56 or 96 bins (selectable) with the bin central frequencies reported in the metadata. The AC cross spectra are duty-cycled such that spectral averaging takes place over the first 1/8 of any given NYs (assuming a 1 NYs data cadence). Less data are averaged by 2^N for cadences faster than 1 NYs by 2^N. For cadences slower than 1 NYs, the first 1/8 of each NYs of data included are averaged together to form the reported data.
The Level 2 data products contained in this data file have been calibrated for:
Note that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz. The units for phase are degrees.
The Level 2 voltage data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer cross spectra data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field cross spectra data are expressed by using search coil magnetometer sensor coordinates with components [u,v,w].
To rotate from [d,e,f] coordinates to [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.
R = [[ 0.46834856, -0.81336422 , 0.34509170]
[ -0.66921924, -0.071546954, 0.73961249]
[ -0.57688408, -0.57733845 , -0.57782790]]
For some orbits, sufficient spectral information exists in the auto spectra and cross spectra to determine wave ellipticity, planarity, and wave normal angles. One method for accomplishing this is presented in reference [4].
Time resolution of the DFB AC cross spectral data can vary by multiples of 2^N. During encounter (when PSP is within 0.25 AU of the Sun), cadence for the DFB AC cross spectra is typically 1 NYsecond [2]. Timestamps correspond to the center time of each window.
References:
Version:2.3.1
PSP FIELDS Digital Fields Board (DFB), XXX ⨯ YYY cross spectra data:
The DFB is the low frequency, less than 75 kHz, component of the FIELDS experiment on the Parker Solar Probe spacecraft, see reference [1] below. For a full description of the FIELDS experiment, see reference [2]. For a description of the DFB, see reference [3].
DFB AC cross spectra data for a pair of input channels consist of:
where all as a function of frequency and time. The last two terms are describedcoherence and phase are defined in [3].
These cross spectra are averaged in both frequency and time as described in [3]. The cross spectra have either 56 or 96 bins (selectable) with the bin central frequencies reported in the metadata. The AC cross spectra are duty-cycled such that spectral averaging takes place over the first 1/8 of any given NYs (assuming a 1 NYs data cadence). Less data are averaged by 2^N for cadences faster than 1 NYs by 2^N. For cadences slower than 1 NYs, the first 1/8 of each NYs of data included are averaged together to form the reported data.
The Level 2 data products contained in this data file have been calibrated for:
Note that compensation for the DFB digital filters will introduce a non-physical positively sloped power trend at high frequencies when the non-corrected signal is dominated by noise. This effect should be examined carefully when determining spectral slopes and features at the highest frequencies. Calibrations for the FIELDS preamplifiers have not been implemented as the preamplifier response is flat and equal to one through the DFB frequency range. Corrections for plasma sheath impedance gain and antenna effective length have not been applied to voltage sensor signals. These corrections will be applied in the Level 3 DFB data products. Therefore, all voltage sensor quantities when present in these Level 2 data products are expressed by using units of Volts squared per Hertz. Likewise, all magnetic field quantities when present in these Level 2 data product are expressed by using units of nanoTesla squared per Hertz. The units for phase are degrees.
The Level 2 voltage data products contained in this data file are expressed in sensor coordinates: e.g. dV12, dV34 for voltage measurements. For solar orbits 1 and 2, the search coil magnetometer cross spectra data are rotated into a non-intuitive coordinate system with components [d,e,f]. For solar orbits 3 and beyond, the magnetic field cross spectra data are expressed by using search coil magnetometer sensor coordinates with components [u,v,w].
To rotate from [d,e,f] coordinates to [u,v,w] search coil sensor coordinates, use the following matrix, written in IDL notation, and the following equation: spectra_uvw_vector = R ## spectra_def_vector.
R = [[ 0.46834856, -0.81336422 , 0.34509170]
[ -0.66921924, -0.071546954, 0.73961249]
[ -0.57688408, -0.57733845 , -0.57782790]]
For some orbits, sufficient spectral information exists in the auto spectra and cross spectra to determine wave ellipticity, planarity, and wave normal angles. One method for accomplishing this is presented in reference [4].
Time resolution of the DFB AC cross spectral data can vary by multiples of 2^N. During encounter (when PSP is within 0.25 AU of the Sun), cadence for the DFB AC cross spectra is typically 1 NYsecond [2]. Timestamps correspond to the center time of each window.
References:
| Role | Person | |
|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Stuart.D.Bale |
| 2. | MetadataContact | spase://SMWG/Person/Robert.M.Candey |
| 3. | MetadataContact | spase://SMWG/Person/Lee.Frost.Bargatze |
Parker Solar Probe, PSP, FIELDS Instrument Suite Description: Bale, S.D., Goetz, K., Harvey, P.R. et al., The FIELDS Instrument Suite for Solar Probe Plus, Space Sci Rev 204, 49–82 (2016)
Parker Solar Probe, PSP, FIELDS Instrument Suite, Digital Fields Board, DFB, Description: Malaspina, D.M., Ergun, R.E., Bolton, M. et al., The Digital Fields Board for the FIELDS Instrument Suite on the Solar Probe Plus Mission: Analog and Digital signal Processing, JGR Space Physics, 121, 5088-5096 (2016)
Parker Solar Probe, PSP, FIELDS Instrument Suite, Data Description, Spacecraft Operations Center, SOC, Web Site, UC Berkeley
Parker Solar Probe, PSP, FIELDS Instrument Suite, Rules of the Road, Spacecraft Operations Center, SOC, Web Site, UC Berkeley
Parker Solar Probe, PSP, Mission Overview, hosted by the Applied Physics Laboratory, Johns Hopkins University
Access to Data in CDF Format via ftp from SPDF
Access to Data in CDF Format via http from SPDF
Access to ASCII, CDF, and Plots via NASA/GSFC CDAWeb
Epoch Time Tags in Terrestrial Time 2000, TT2000, for Digital Fields Board, DFB, AC-coupled SCMdlfhg-SCMelfhg Cross Spectra
FIELDS Digital Fields Board, DFB, Frequency Bins for AC-coupled SCMdlfhg-SCMelfhg Cross Spectra
Auto Spectra, Power, channel SCMelfhg
Saturation Flags for Auto Spectra, Power, channel SCMdlfhg
Auto Spectra, Power, channel SCMelfhg
Saturation Flags for Auto Spectra, Power, channel SCMelfhg
Cross Spectra, Coherence between channels SCMdlfhg-SCMelfhg
Saturation Flags for Cross Spectra, Coherence between channels SCMdlfhg-SCMelfhg
Cross Spectra, Phase of channel SCMelfhg relative to channel SCMdlfhg
Saturation Flags for Cross Spectra, Phase of channel SCMelfhg relative to channel SCMdlfhg
Cross Spectra, Real Part (co-spectra) of the Fourier Transfrom cross term (FT₁ ⨯ FT₂*), channels SCMdlfhg-SCMelfhg
Saturation Flags for Cross Spectra, Real Part of the Fourier Transfrom cross term (FT₁ ⨯ FT₂*), channels SCMdlfhg-SCMelfhg
Cross Spectra, Imaginary Part (quadrature) of the Fourier Transfrom cross term (FT₁ ⨯ FT₂*), channels SCMdlfhg-SCMelfhg
Saturation Flags for Cross Spectra, Imaginary Part of the Fourier Transfrom cross term, channels SCMdlfhg-SCMelfhg
Epoch Time Tags in Terrestrial Time 2000, TT2000, for FIELDS Instrument Suite Data Quality Flags
FIELDS Instrument Suite Data Quality Flags
Rotation Matrix from (d,e,f) to (u,v,w) Coordinates