FPI Datasets

Fast Plasma Investigation (FPI)
The Fast Plasma Investigation (FPI) includes four dual electron spectrometers (DES) and four dual ion spectrometers (DIS) per spacecraft. When the data from the two sets of four dual-spectrometers are combined, FPI is able to provide the velocity-space distribution of electrons from 10 eV to 30 keV and ions from 10 eV to 30 keV with a time resolution of 30 ms, and 150 ms, respectively (Pollock et al., 2014).>.

For questions about the technical details of FPI or its data products, contact the FPI Lead Co-I: Dr. B. L. Giles, NASA GSFC
Data Products Guide
The FPI Data Product Guide contains an overview of the FPI data products. Included in the guide is a listing of the variables (with a description of the variable, units, and data type), naming conventions for files and variables, quality flag descriptions, and known features of the FPI Level-2, Quicklook, and SITL data products. This Data Product Guide is hosted online and will be updated as needed by the FPI Instrument Team.

Version Release Notes
Users interested in FPI data are strongly encouraged to familiarize themselves with the Version Release Notes, the full extent of which are included in the following pdf:
FPI Version Release Notes.

Included in the Version Release Notes are Caveats, Known features, and Helpful information on how to use and interpret the data. Any questions regarding the data should be addressed to the FPI science team.
MMS-4 FPI Anomaly
NOTICE TO ALL FPI DATA USERS
On 7 June 2018 12:43 UTC, the MMS Fast Plasma Investigation (FPI) suffered its first impactful flight anomaly since launching in March, 2015. The electron spectrometer pair at quadrant 1 on MMS4 experienced a failure that appears non-recoverable. The symptoms – repeatable after further contact, reset, and commanding of the instrument – were a sustained high current draw and the absence of counts from this spectrometer pair. The spectrometer pair has been turned off. On 15 July 2018 00:47 UTC, the MMS FPI suffered its second impactful flight anomaly. The electron spectrometer pair at quadrant 0 on MMS4 experienced a similar failure that appears to be non-recoverable and this unit was also turned off. These failures appear to be unrelated.

One half of the contiguous solid angle space in each electron plasma distribution on the MMS4 spacecraft is impacted. To mitigate the scientific impact, level 2 MMS4 DES fast survey and burst distribution (des-dist) files reflecting post-anomaly data will contain fill data for angle space affected by the sensor outages. Lower temporal resolution MMS4 DES fast survey moments (des-moms) files for post-anomaly data will also be released. The FPI ground system team is continuing to analyze options for potential release of MMS4 DES post-anomaly burst moments.

There remain a full complement of operational spectrometers on the other three MMS spacecraft. In addition, the FPI ion spectrometers and corresponding MMS4 FPI ion data is also unaffected.

Further inquiries may be directed to the FPI Lead Co-I, Barbara Giles, at barbara.giles@nasa.gov.
FPI Data Variables
Click on the dataset name for information about the file content.
Note: Due to the number of variables in each file, not all are shown below.

Level-2 Fast Survey Distributions

File Name Pattern: MMS[1,2,3,4]_FPI_FAST_L2_DES-DIST_YYYYMMDDHHMMSS_V2.1.0.cdf
File Name Pattern: MMS[1,2,3,4]_FPI_FAST_L2_DIS-DIST_YYYYMMDDHHMMSS_V2.1.0.cdf
Sensor Data Mode Variable Name Units Comments
DES/DIS Fast EPOCH ns Survey data acquisition time; derived from packet time.
DES/DIS Fast/td> MMS_DES_DIST_FAST d Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DES/DIS Fast/td> MMS_DES_DISTERR_FAST [# / {(cm/s)3 * cc}] Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DES/DIS Fast MMS_DES_THETA_FAST degrees Pixel zenith angles.
DES/DIS Fast MMS_DES_ENERGY_FAST eV Geometric mean of parity 0 and parity 1 energies in the 64-step FPI energy table.
DES/DIS Fast MMS_DES_PHI_FAST degrees Azimuth Angles

Level-2 DES Burst Distributions.

File Name Pattern: MMS[1,2,3,4]_FPI_BRST_L2_DES-DIST_YYYYMMDDHHMMSS_V2.1.0.cdf
Sensor Data Mode Variable Name Units Comments
DES Burst Epoch ns Survey data acquisition time; derived from packet time.
DES Burst MMS_DES_PHI_BRST degrees MMS1 FPI/DES burst sky-map instrument azimuthal angles
DES Burst MMS_DES_DIST_BRST [# / {(cm/s)3 * cc}] Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DES Burst MMS_DES_DISTERR_BRST [# / {(cm/s)3 * cc}] Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DES Burst MMS_DES_ENERGY1_BRST eV Odd energies (parity 1) in the 64-step FPI energy table
DES Burst MMS_DES_ENERGY0_BRST eV Even energies (parity 0) in the 64-step FPI energy table

Level-2 DIS Burst Distributions

File Name Pattern: MMS[1,2,3,4]_FPI_BRST_L2_DIS-DIST_YYYYMMDDHHMMSS_V2.1.0.cdf
Sensor Data Mode Variable Name Units Comments
DIS Burst Epoch ns Survey data acquisition time; derived from packet time.
DIS Burst MMS_DIS_PHI_BRST degrees MMS FPI/DIS burst sky-map instrument azimuthal angles
DIS Burst MMS_DIS_DIST_BRST [# / {(cm/s)3 * cc}] Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DIS Burst MMS_DIS_DISTERR_BRST [# / {(cm/s)3 * cc}] Az bin: sector ind=00 looks "after" (spin-phase) Sun, ..., sector ind=31 looks "before" Sun dir. Head field-of-view: pixel index=00 looks to zenith, ..., pixel index=15 looks to nadir. FPI operations nominally bin data from 64 energy filters into 32 pairwise energy bins, indexed 0-31. Nominally, bins are indexed in increasing energy order. See FPI docs for details.
DIS Burst MMS_DIS_ENERGY1_BRST eV Odd energies (parity 1) in the 64-step FPI energy table
DIS Burst MMS_DIS_ENERGY0_BRST eV Even energies (parity 0) in the 64-step FPI energy table

Level-2 Moments

File Name Pattern: MMS[1,2,3,4]_FPI_FAST_L2_DES-MOMS_YYYYMMDDHHMMSS_V2.1.0.cdf
File Name Pattern: MMS[1,2,3,4]_FPI_FAST_L2_DIS-MOMS_YYYYMMDDHHMMSS_V2.1.0.cdf
File Name Pattern: MMS[1,2,3,4]_FPI_BRST_L2_DES-MOMS_YYYYMMDDHHMMSS_V2.1.0.cdf
File Name Pattern: MMS[1,2,3,4]_FPI_BRST_L2_DIS-MOMS_YYYYMMDDHHMMSS_V2.1.0.cdf
Sensor Data Mode Variable Name Units Comments
DES/DIS Fast/Burst Epoch ns Survey data acquisition time; derived from packet time.
DES/DIS Fast/Burst MMS_DES_STARTDELPHI_ANGLE_BRST degrees Nominally, spin-phase angles range over [0, 360) deg. Each count represents 1/16 deg of observatory spin-phase. Zero spin-phase angle indicates obs +X-axis aligned with Sun.
DES/DIS Fast/Burst MMS_DES_PITCHANGDIST_LOWEN_BURST ----- low energy bin: 0 eV - 200 eV. pitch-angle bin size: 6 deg.
DES/DIS Fast/Burst MMS_DES_PITCHANGDIST_MIGEN_BURST ----- mid energy bin: 2000 eV - 2 keV. pitch-angle bin size: 6 deg.
DES/DIS Fast/Burst MMS_DES_PITCHANGDIST_HIGHEN_BURST ----- high energy bin: 2 keV - 30 keV. pitch-angle bin size: 6 deg.
DES/DIS Fast/Burst MMS_DES_ENERGYSPECTR_[P,M][X,Y,Z] ----- Counts, summed over DSC velocity-dirs closest to -[X,Y,Z]_DSC, by energy bin.
DES/DIS Fast/Burst MMS_DES_NUMBERDENSITY_DBSC_BRST cm^-3 Number Density
DES/DIS Fast/Burst MMS_DES_BULKSPEED_DBSC_BRST km/s Bulk Speed
DES/DIS Fast/Burst MMS_DES_BULK[X,Y,Z]_DBSC_BRST km/s Bulk velocity vector GSE [X,Y,Z] component.
DES/DIS Fast/Burst MMS_DES_PRES[X,Y,Z][X,Y,Z]_DBSC_BRST erg/cm^3 Pressure tensor GSE [X,Y,Z][X,Y,Z] component
DES/DIS Fast/Burst MMS_DES_TEMP[X,Y,Z][X,Y,Z]_DBSC_BRST eV Temperature tensor GSE [X,Y,Z][X,Y,Z] component
DES/DIS Fast/Burst MMS_DES_HEATFLUX_DBSC_BRST (erg/s)/cm^2 Heat flux vector magnitude
DES/DIS Fast/Burst MMS_DES_ALPHA_BRST degrees Pitch-angles angles used in pitch angle spectrograms (bent Pipe field)
DES/DIS Fast/Burst MMS_DES_ENERGY1_BRST eV Odd energies (parity 1) in the 64-step FPI energy table
DES/DIS Fast/Burst MMS_DES_ENERGY0_BRST eV Even energies (parity 0) in the 64-step FPI energy table
DES/DIS Fast/Burst MMS_DES_TEMPPARA_BRST eV Parallel temperature
DES/DIS Fast/Burst MMS_DES_TEMPPERP_BRST eV Perpendicular temperature
Most Recent Files