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MMS 2 Electron Drift Instrument (EDI) Ambient Electron Flux, Projection Method 1 (PM1), Level 2 (L2), Burst Mode, 0.9765625 ms Data

Electron Drift Instrument (EDI) Ambient Burst Survey, Level 2, 0.0009765625 s Data (1024 samples/s). EDI has two scientific data acquisition modes, called electric field mode and ambient mode. In electric field mode, two coded electron beams are emitted such that they return to the detectors after one or more gyrations in the ambient magnetic and electric field. The firing directions and times-of-flight allow the derivation of the drift velocity and electric field. In ambient mode, the electron beams are not used. The detectors with their large geometric factors and their ability to adjust the field of view quickly allow continuous sampling of ambient electrons at a selected pitch angle and fixed but selectable energy. To find the beam directions that will hit the detector, EDI sweeps each beam in the plane perpendicular to B at a fixed angular rate of 0.22 °/ms until a signal has been acquired by the detector. Once signal has been acquired, the beams are swept back and forth to stay on target. Beam detection is not determined from the changes in the count-rates directly, but from the square of the beam counts divided by the background counts from ambient electrons, i.e., from the square of the instantaneous signal-to-noise ratio (SNR). This quantity is computed from data provided by the correlator in the Gun-Detector Electronics that also generates the coding pattern imposed on the outgoing beams. If the squared SNR ratio exceeds a threshold, this is taken as evidence that the beam is returning to the detector. The thresholds for SNR are chosen dependent on background fluxes. They represent a compromise between getting false hits (induced by strong variations in background electron fluxes) and missing true beam hits. The basic software loop that controls EDI operations is executed every 2 ms. As the times when the beams hit their detectors are neither synchronized with the telemetry nor equidistant, EDI data have no fixed time-resolution. Data are reported in telemetry slots. In Survey, using the standard packing mode 0, there are eight telemetry slots per second and Gyn Detector Unit (GDU). The last beam detected during the previous slot will be reported in the current slot. If no beam has been detected, the data quality will be set to zero. In Burst telemetry there are 128 slots per second and GDU. The data in each slot consists of information regarding the beam firing directions (stored in the form of analytic gun deflection voltages), times-of-flight (if successfully measured), quality indicators, time stamps of the beam hits, and some auxiliary correlator-related information. Whenever EDI is not in electron drift mode, it uses its ambient electron mode. The mode has the capability to sample at either 90 degrees pitch angle or at 0/180 degrees (field aligned), or to alternate between 90 degrees and field aligned with selectable dwell times. While all options have been demonstrated during the commissioning phase, only the field aligned mode has been used in the routine operations phase. The choices for energy are 250 eV, 500 eV, and 1 keV. The two detectors, which are facing opposite hemispheres, are looking strictly into opposite directions, so while one detector is looking along B the other is looking antiparallel to B (corresponding to pitch angles of 180 and 0 degrees, respectively). The two detectors switch roles every half spin of the spacecraft as the tip of the magnetic field vector spins outside the field of view of one detector and into the field of view of the other detector. Up until January 4, 2016 the anodes were chosen such that the magnetic field vector projected into the plane of the micro-channel plate entry surface was best aligned with the center of the four anodes ( that is, with the gap between the inner two of the four anodes). Data taken in this configuration are using the term "amb" in the data product names. In the burst data where four channels (corresponding to the four adjacent sensor anode pads) are sampled per GDU, the average (or sum) of the center two channels (channels 2 and 3) represents best the pitch angle of 0 degrees (or 180 degrees). The EDI instrument paper can be found at: http://link.springer.com/article/10.1007%2Fs11214-015-0182-7. The EDI instrument data products guide can be found at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

MMS 3 Energetic Particle Detector, Energetic Ion Spectrometer (EPD-EIS) Pulse Height by Time of Flight, Level 2 (L2), Burst Mode, 0.605 s Data

Energetic Particle Detector (EPD), Energetic Ion Spectrometer (EIS) Pulse Height by Time of Flight, Level 2, Burst Survey, 0.605 s Data. The EIS provides ion composition measurements (protons versus oxygen ions) and angular distributions over the energy range from approximately 45 to 500 keV.

MMS 1 Electron Drift Instrument (EDI) Quality 0 Counts, Level 2 (L2), Burst Mode, 7.8125 ms Data

Electron Drift Instrument (EDI) Q0 Burst Survey, Level 2, 0.0078125 s Data (128 samples/s). EDI has two scientific data acquisition modes, called electric field mode and ambient mode. In electric field mode, two coded electron beams are emitted such that they return to the detectors after one or more gyrations in the ambient magnetic and electric field. The firing directions and times-of-flight allow the derivation of the drift velocity and electric field. In ambient mode, the electron beams are not used. The detectors with their large geometric factors and their ability to adjust the field of view quickly allow continuous sampling of ambient electrons at a selected pitch angle and fixed but selectable energy. To find the beam directions that will hit the detector, EDI sweeps each beam in the plane perpendicular to B at a fixed angular rate of 0.22 °/ms until a signal has been acquired by the detector. Once signal has been acquired, the beams are swept back and forth to stay on target. Beam detection is not determined from the changes in the count-rates directly, but from the square of the beam counts divided by the background counts from ambient electrons, i.e., from the square of the instantaneous signal-to-noise ratio (SNR). This quantity is computed from data provided by the correlator in the Gun-Detector Electronics that also generates the coding pattern imposed on the outgoing beams. If the squared SNR ratio exceeds a threshold, this is taken as evidence that the beam is returning to the detector. The thresholds for SNR are chosen dependent on background fluxes. They represent a compromise between getting false hits (induced by strong variations in background electron fluxes) and missing true beam hits. The basic software loop that controls EDI operations is executed every 2 ms. As the times when the beams hit their detectors are neither synchronized with the telemetry nor equidistant, EDI data have no fixed time-resolution. Data are reported in telemetry slots. In Survey, using the standard packing mode 0, there are eight telemetry slots per second and Gyn Detector Unit (GDU). The last beam detected during the previous slot will be reported in the current slot. If no beam has been detected, the data quality will be set to zero. In Burst telemetry there are 128 slots per second and GDU. The data in each slot consists of information regarding the beam firing directions (stored in the form of analytic gun deflection voltages), times-of-flight (if successfully measured), quality indicators, time stamps of the beam hits, and some auxiliary correlator-related information. Whenever EDI is not in electron drift mode, it uses its ambient electron mode. The mode has the capability to sample at either 90 degrees pitch angle or at 0/180 degrees (field aligned), or to alternate between 90 degrees and field aligned with selectable dwell times. While all options have been demonstrated during the commissioning phase, only the field aligned mode has been used in the routine operations phase. The choices for energy are 250 eV, 500 eV, and 1 keV. The two detectors, which are facing opposite hemispheres, are looking strictly into opposite directions, so while one detector is looking along B the other is looking antiparallel to B (corresponding to pitch angles of 180 and 0 degrees, respectively). The two detectors switch roles every half spin of the spacecraft as the tip of the magnetic field vector spins outside the field of view of one detector and into the field of view of the other detector. These data are a by-product generated from data collected in electric field mode. Whenever no return beam is found in a particular time slot by the flight software to be reported will be flagged with the lowest quality level (quality zero). The ground processing generates a separate data product from these counts data. The EDI instrument paper can be found at: http://link.springer.com/article/10.1007%2Fs11214-015-0182-7. The EDI instrument data products guide can be found at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

MMS 1 Electron Drift Instrument (EDI) Electric Field, Level 2 (L2), Burst Mode, 0.9765625 ms Data

Electron Drift Instrument (EDI) Electric Field Burst Survey, Level 2, 0.0009765625 s Data (1024 samples/s). EDI has two scientific data acquisition modes, called electric field mode and ambient mode. In electric field mode, two coded electron beams are emitted such that they return to the detectors after one or more gyrations in the ambient magnetic and electric field. The firing directions and times-of-flight allow the derivation of the drift velocity and electric field. In ambient mode, the electron beams are not used. The detectors with their large geometric factors and their ability to adjust the field of view quickly allow continuous sampling of ambient electrons at a selected pitch angle and fixed but selectable energy. To find the beam directions that will hit the detector, EDI sweeps each beam in the plane perpendicular to B at a fixed angular rate of 0.22 °/ms until a signal has been acquired by the detector. Once signal has been acquired, the beams are swept back and forth to stay on target. Beam detection is not determined from the changes in the count-rates directly, but from the square of the beam counts divided by the background counts from ambient electrons, i.e., from the square of the instantaneous signal-to-noise ratio (SNR). This quantity is computed from data provided by the correlator in the Gun-Detector Electronics that also generates the coding pattern imposed on the outgoing beams. If the squared SNR ratio exceeds a threshold, this is taken as evidence that the beam is returning to the detector. The thresholds for SNR are chosen dependent on background fluxes. They represent a compromise between getting false hits (induced by strong variations in background electron fluxes) and missing true beam hits. The basic software loop that controls EDI operations is executed every 2 ms. As the times when the beams hit their detectors are neither synchronized with the telemetry nor equidistant, EDI data have no fixed time-resolution. Data are reported in telemetry slots. In Survey, using the standard packing mode 0, there are eight telemetry slots per second and Gyn Detector Unit (GDU). The last beam detected during the previous slot will be reported in the current slot. If no beam has been detected, the data quality will be set to zero. In Burst telemetry there are 128 slots per second and GDU. The data in each slot consists of information regarding the beam firing directions (stored in the form of analytic gun deflection voltages), times-of-flight (if successfully measured), quality indicators, time stamps of the beam hits, and some auxiliary correlator-related information. Whenever EDI is not in electron drift mode, it uses its ambient electron mode. The mode has the capability to sample at either 90 degrees pitch angle or at 0/180 degrees (field aligned), or to alternate between 90 degrees and field aligned with selectable dwell times. While all options have been demonstrated during the commissioning phase, only the field aligned mode has been used in the routine operations phase. The choices for energy are 250 eV, 500 eV, and 1 keV. The two detectors, which are facing opposite hemispheres, are looking strictly into opposite directions, so while one detector is looking along B the other is looking antiparallel to B (corresponding to pitch angles of 180 and 0 degrees, respectively). The two detectors switch roles every half spin of the spacecraft as the tip of the magnetic field vector spins outside the field of view of one detector and into the field of view of the other detector. This is the primary data product generated from data collected in electric field mode. The science data generated are drift velocity and electric field data in various coordinate systems. They are derived from triangulation and/or time-of-flight analysis. Where both methods are applicable, their results will be combined using a weighting approach based on their relative errors. The EDI instrument paper can be found at: http://link.springer.com/article/10.1007%2Fs11214-015-0182-7. The EDI instrument data products guide can be found at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

MMS 4 Energetic Particle Detector, Energetic Ion Spectrometer (EPD-EIS) Energy by Time of Flight, Level 2 (L2), Burst Mode, 0.605 s Data

Energetic Particle Detector (EPD), Energetic Ion Spectrometer (EIS) Energy by Time of Flight, Level 2, Burst Survey, 0.605 s Data. The EIS provides ion composition measurements (protons versus oxygen ions) and angular distributions over the energy range from approximately 45 to 500 keV.

MMS 1 Electric Particle Detector, Fly's Eye Energetic Particle Sensor (EPD, FEEPS) Electrons, Level 2 (L2), Burst Mode, 0.3025 s Data

Fly's Eye Electron Proton Spectrometer (FEEPS) Burst Data. The Energetic Particle Detector (EPD) investigation aboard the four MMS spacecraft consists of two instrument designs, the FEEPS and the EIS (Energetic Ion Spectrometer). A FEEPS consists of six Heads, each composed of two Eyes. Each eye is a particle telescope with a single silicon detector. There are nine electron eyes and three ion eyes per FEEPS. The energy coverage is from 25 keV to 650 keV for electrons and 45 keV to 650 keV for ions. Each eye has sixteen energy channels, the spacing of which can be modified by command. The fields of view and pointing of each eye are designed to provide a broad, instantaneous field of view for the twelve eyes per FEEPS.

MMS 1 Electric Particle Detector, Fly's Eye Energetic Particle Sensor (EPD, FEEPS) Ions, Level 2 (L2), Burst Mode, 0.3025 s Data

STEREO-A In-Situ Measurements of Particles and CME Transients (IMPACT) Fluxgate Magnetometer (MAG) Burst Mode, Magnetic Field Vector, Spacecraft (SC) Coordinates, Level 1 (L1), 31 ms Data

This data product contains Level 1 0.03125-s or 32 Hz burst-mode values of solar wind magnetic field data measured by the IMPACT Magnetometer on STEREO-A in Spacecraft, SC, coordinates.

MMS 3 Search Coil Magnetometer (SCM) AC Magnetic Field Level 2 (L2), High Speed Burst Mode, 16384 Sample/s Data

Search Coil Magnetometer (SCM) AC Magnetic Field (16384 samples/s), Level 2, High Speed Burst Mode Data. The tri-axial Search-Coil Magnetometer with its associated preamplifier measures three-dimensional magnetic field fluctuations. The analog magnetic waveforms measured by the SCM are digitized and processed inside the Digital Signal Processor (DSP), collected and stored by the Central Instrument Data Processor (CIDP) via the Fields Central Electronics Box (CEB). Prior to launch, all SCM Flight models were calibrated by LPP team members at the National Magnetic Observatory, Chambon-la-Foret (Orleans). Once per orbit, each SCM transfer function is checked thanks to the onboard calibration signal provided by the DSP. The SCM is operated for the entire MMS orbit in survey mode. Within scientific Regions Of Interest (ROI), burst mode data are also acquired as well as high speed burst mode data. This SCM data set corresponds to the AC magnetic field waveforms in nanoTesla and in the GSE frame. The SCM instrument paper for SCM can be found at http://link.springer.com/article/10.1007/s11214-014-0096-9 and the SCM data product guide at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

MMS 3 Electron Drift Instrument (EDI) Electric Field, Level 2 (L2), Burst Mode, 0.9765625 ms Data

CGRO/BATSE 5B Gamma-Ray Burst Spectral Catalog

The CGRO/BATSE 5B Gamma-Ray Burst Spectral Catalog contains the results of systematic spectral analyses of gamma-ray bursts (GRBs) detected with the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma-Ray Observatory (CGRO) during its entire nine years of operation. This catalog contains two types of spectra extracted from 2,145 GRBs, and fitted with five different spectral models resulting in a compendium of over 19,000 spectra. The models were selected based on their empirical importance to the spectral shape of many GRBs, and the analysis performed was devised to be as thorough and objective as possible. In their paper, the authors describe in detail their procedures and criteria for the analyses, and present the bulk results in the form of parameter distributions. This catalog should be considered an official product from the BATSE Science Team, and the data files containing the complete results are soon to be available from the HEASARC. This table lists all of the spectroscopy results of gamma-ray bursts observed by a subset of the 8 BATSE Large Area Detectors. BATSE consisted, in part, of an array of 8 sodium iodide Large Area Detectors (LADs) which covered the energy range from ~20 keV - 2 MeV. The LAD detectors were placed at each of the eight corners of the CGRO spacecraft with an outward orientation such that the entire sky not occulted by the Eartt was observed. The spectrum files ("scat" files) available as FITS-format data products associated with this catalog provide parameter values and goodness-of-fit measures for different types of spectral fits and models. These fits are performed using 14-channel data, usually 2-second resolution CONT data. There are currently two spectrum categories: <pre> * Peak flux ('pflx') - a single spectrum over a 2.05-second time range at the peak flux of the burst * Fluence ('flnc') - a single spectrum over the entire burst duration </pre> The quoted fluxes and fluences are for the 20 keV - 2 MeV energy range, notice. The scat files have two extensions. The first extension gives detector-specific information, including photon fluxes and fluences for each detector, which are provided for each energy channel. The second extension provides derived quantities such as flux, fluence and model parameters for the joint fit of all included detectors. The scat files and their energy-resolved quantities contained in these two extensions will be available soon in the HEASARC data archive. Quantities derived from these spectral fits are available in the present table, as described below and in the Goldstein et al. (2013) reference paper. The spectra are fit with a number of models, with the signal-to-noise ratio of the spectrum often determining whether a more complex model is statistically favored. The current set is: <pre> * Power law ('plaw'), * Comptonized (exponentially attenuated power law; 'comp') * Band ('band') * Smoothly broken power law ('sbpl') * Log_10 Gaussian ('glog') </pre> The full details of these models are presented in Section 4 of the reference paper. The type of spectrum and spectral model are coded into the parameter names (and the associated file names) using the acronyms given above. Thus for example, the parameters with names beginning with 'flnc_glog' contain the results from fits to the fluence spectra using Log<sub>10</sub> Gaussian models. The corresponding spectrum file for the burst with trigger number 105 with the results from a fit to the fluence spectrum using a Log<sub>10</sub> Gaussian model is named scat_0105_flnc_glog_v00.fit. Please note that this table lists the raw results of each spectral fit to each GRB. In cases where the spectral fit failed, the values reported are those that initialized the spectral fit. If the uncertainty on the spectral parameters is reported as zero (no uncertainty), then the fit failed. In a few cases throughout this table, the uncertainties for certain spectral parameters may be reported as '9999.99' which indicates that the uncertainty on that parameter is completely unconstrained. An example of this is when the spectral data from a burst is fitted with a BAND function but is unable to constrain the high-energy index. In this case, the best fit centroid value of the high-energy index parameter is reported, and the '9999.99' value is reported for the uncertainty. This table was created by the HEASARC in November 2013 based on electronic versions of Tables 6 through 10, inclusive, from the reference paper which were obtained from the ApJS web site. This is a service provided by NASA HEASARC .

Fermi GBM Burst Catalog

When referencing results from this online catalog, please cite <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ab7a18">von Kienlin, A. et al. 2020</a>, <a href="http://iopscience.iop.org/0067-0049/211/1/12/">Gruber, D. et al. 2014</a>, <a href="http://iopscience.iop.org/0067-0049/211/1/13/">von Kienlin, A. et al. 2014</a>, and <a href="http://iopscience.iop.org/article/10.3847/0067-0049/223/2/28/">Bhat, P. et al. 2016</a>. This table lists all of the triggers observed by a subset of the 14 GBM detectors (12 NaI and 2 BGO) which have been classified as gamma-ray bursts (GRBs). Note that there are two Browse catalogs resulting from GBM triggers. All GBM triggers are entered in the <a href="/W3Browse/fermi/fermigtrig.html">Fermi GBM Trigger Catalog</a>, while only those triggers classified as bursts are entered in the Burst Catalog. Thus, a burst will be found in both the Trigger and Burst Catalogs. The Burst Catalog analysis requires human intervention; therefore, GRBs will be entered in the Trigger Catalog before the Burst Catalog. The latency requirements are 1 day for triggers and 3 days for bursts. There are four fewer bursts in the online catalog than in the Gruber et al. 2014 paper. The four missing events (081007224, 091013989, 091022752, and 091208623) have not been classified with certainty as GRBs and are not included in the general GRB catalog. This classification may be revised at a later stage. The GBM consists of an array of 12 sodium iodide (NaI) detectors which cover the lower end of the energy range up to 1 MeV. The GBM triggers off of the rates in the NaI detectors, with some Terrestrial Gamma-ray Flash (TGF)-specific algorithms using the bismuth germanate (BGO) detectors, sensitive to higher energies, up to 40 MeV. The NaI detectors are placed around the Fermi spacecraft with different orientations to provide the required sensitivity and FOV. The cosine-like angular response of the thin NaI detectors is used to localize burst sources by comparing rates from detectors with different viewing angles. The two BGO detectors are placed on opposite sides of the spacecraft so that all sky positions are visible to at least one BGO detector. The signals from all 14 GBM detectors are collected by a central Data Processing Unit (DPU). This unit digitizes and time-tags the detectors' pulse height signals, packages the resulting data into several different types for transmission to the ground (via the Fermi spacecraft), and performs various data processing tasks such as autonomous burst triggering. The GRB science products are transmitted to the FSSC in two types of files. The first file, called the "bcat" file, provides basic burst parameters such as duration, peak flux and fluence, calculated from 8-channel data using a spectral model which has a power-law in energy that falls exponentially above an energy EPeak, known as the Comptonized model. The crude 8-channel binning and the simple spectral model allow data fits in batch mode over numerous time bins in an efficient and robust fashion, including intervals with little or no flux, yielding both values for the burst duration, and deconvolved lightcurves for the detectors included in the fit. The bcat file includes two extensions. The first, containing detailed information about energy channels and detectors used in the calculations, is detector-specific, and includes the time history of the deconvolved flux over the time intervals of the burst. The second shows the evolution of the spectral parameters obtained in a joint fit of the included detectors for the model used, usually the Comptonized model described above. The bcat files and their time-varying quantities contained in these two extensions are available at the HEASARC FTP site. Quantities derived from these batch fits are given in the bcat primary header and presented in the Browse table, as described below. The main purpose of the analysis contained in the bcat file is to produce a measure of the duration of the burst after deconvolving the instrument response. The duration quantities are: <pre> * 't50' - the time taken to accumulate 50% of the burst fluence starting at the 25% fluence level. * 't90' - the time taken to accumulate 90% of the burst fluence starting at the 5% fluence level. </pre> By-products of this analysis include fluxes on various timescales and fluences, both obtained using the simple Comptonized model described above. These quantities are detailed in the Browse table using the following prefixes: <pre> * 'flux' - the peak flux over 3 different timescales obtained in the batch mode fit used to calculate t50/t90. * 'fluence' - the total fluence accumulated in the t50/t90 calculation. </pre> The fluxes and fluences derived from the 8-channel data for these bcat files should be considered less reliable than those in the spectral analy

MMS 4 Fast Plasma Investigation, Dual Electron Spectrometer (FPI, DES) Distribution Moments, Level 2 (L2), Burst Mode, 30 ms Data

The Fast Plasma Instrument (FPI) usually Operates in Fast Survey (FS) Mode in the MMS Region Of Interest (ROI) for the current Mission Phase. Data are taken at Burst (30/150 ms for DES/DIS) Resolution in this Mode. Data are also made available at Survey (4.5 s, etc.) Resolution. Per Mission Design, not all Burst Resolution Data are downlinked, but all Survey Data are downlinked. Planning around Calibration Activities, avoidance of Earth Radiation Belts, etc., when possible, FPI usually Operates in Slow Survey (SS) Mode outside of ROI, and then only the 60 s Resolution Survey Data are available. This Product contains Results from integrating the standard Moments of Phase Space Distributions formed from the indicated Data Type (DES/DIS Burst, FS or SS). For Convenience, some additional Parameters are included to augment those most commonly found in a Moments Product of this sort, plus Time Stamps and other Annotation characterizing the State of the Instrument System at the indicated Time.

MMS 4 Fast Plasma Investigation, Dual Ion Spectrometer (FPI, DIS) Partial Distribution Moments, Level 2 (L2), Burst Mode, 0.15 s Data

FPI usually operates in Fast Survey (FS) Mode in the MMS Region Of Interest (ROI) for the current Mission Phase. Data are taken at Burst (30/150 ms for DES/DIS) Resolution in this Mode. Data are also made available at Survey (4.5 s, etc.) Resolution. Per Mission Design, not all Burst Resolution Data are downlinked, but all Survey Data are downlinked. Planning around Calibration Activities, avoidance of Earth Radiation Belts, etc., when possible, FPI usually operates in Slow Survey (SS) Mode (60 s Resolution) outside of ROI, and then only the 60 s Resolution Survey Data are available. This Product contains Partial Moments that come from performing the Standard Moment Integrals over a limited Portion of Velocity Space. The resulting Quantities are named similarly to their corresponding Standard Moments, but are decorated with 'part' to differentiate. For example, density_part is the Density Moment integrated from a particular Energy Step to Infinity. These Partial Moments are formed from the indicated Data Type (DES/DIS Burst, FS or SS). For convenience, some additional Parameters are included to augment those most commonly found in a Moments Product of this sort, plus Time Stamps and other Annotation characterizing the State of the Instrument System at the indicated Time.

MMS 2 Electron Drift Instrument (EDI) Ambient Electron Flux, Projection Method 2 (PM2), Level 2 (L2), Burst Mode, 0.9765625 ms Data

Electron Drift Instrument (EDI) Ambient Burst Survey, Level 2, 0.0009765625 s Data (1024 samples/s). EDI has two scientific data acquisition modes, called electric field mode and ambient mode. In electric field mode, two coded electron beams are emitted such that they return to the detectors after one or more gyrations in the ambient magnetic and electric field. The firing directions and times-of-flight allow the derivation of the drift velocity and electric field. In ambient mode, the electron beams are not used. The detectors with their large geometric factors and their ability to adjust the field of view quickly allow continuous sampling of ambient electrons at a selected pitch angle and fixed but selectable energy. To find the beam directions that will hit the detector, EDI sweeps each beam in the plane perpendicular to B at a fixed angular rate of 0.22 °/ms until a signal has been acquired by the detector. Once signal has been acquired, the beams are swept back and forth to stay on target. Beam detection is not determined from the changes in the count-rates directly, but from the square of the beam counts divided by the background counts from ambient electrons, i.e., from the square of the instantaneous signal-to-noise ratio (SNR). This quantity is computed from data provided by the correlator in the Gun-Detector Electronics that also generates the coding pattern imposed on the outgoing beams. If the squared SNR ratio exceeds a threshold, this is taken as evidence that the beam is returning to the detector. The thresholds for SNR are chosen dependent on background fluxes. They represent a compromise between getting false hits (induced by strong variations in background electron fluxes) and missing true beam hits. The basic software loop that controls EDI operations is executed every 2 ms. As the times when the beams hit their detectors are neither synchronized with the telemetry nor equidistant, EDI data have no fixed time-resolution. Data are reported in telemetry slots. In Survey, using the standard packing mode 0, there are eight telemetry slots per second and Gyn Detector Unit (GDU). The last beam detected during the previous slot will be reported in the current slot. If no beam has been detected, the data quality will be set to zero. In Burst telemetry there are 128 slots per second and GDU. The data in each slot consists of information regarding the beam firing directions (stored in the form of analytic gun deflection voltages), times-of-flight (if successfully measured), quality indicators, time stamps of the beam hits, and some auxiliary correlator-related information. Whenever EDI is not in electron drift mode, it uses its ambient electron mode. The mode has the capability to sample at either 90 degrees pitch angle or at 0/180 degrees (field aligned), or to alternate between 90 degrees and field aligned with selectable dwell times. While all options have been demonstrated during the commissioning phase, only the field aligned mode has been used in the routine operations phase. The choices for energy are 250 eV, 500 eV, and 1 keV. The two detectors, which are facing opposite hemispheres, are looking strictly into opposite directions, so while one detector is looking along B the other is looking antiparallel to B (corresponding to pitch angles of 180 and 0 degrees, respectively). The two detectors switch roles every half spin of the spacecraft as the tip of the magnetic field vector spins outside the field of view of one detector and into the field of view of the other detector. Starting January 4, 2016, the anodes were chosen such that the projection of the magnetic field vector was best aligned with the center of the first (that is, outer) of the four anodes. This provides coverage of a larger range of pitch angles in general. Data taken in this configuration are identified by the term "amb-pm2" in the data product names. In the burst data where four channels (corresponding to the four adjacent sensor anode pads) are sampled per GDU, channel 1 represents best the pitch angle of 0 degrees (or 180 degrees). The EDI instrument paper can be found at: http://link.springer.com/article/10.1007%2Fs11214-015-0182-7. The EDI instrument data products guide can be found at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

FAST Electrostatic Analyzer (ESA), Electron Burst 0.156 s Data

The FAST IES and EES measure 32 pitch angle directions simultaneously, 11.25° resolution, and sweep over 48 energy steps in 1/64 of a spacecraft spin. The energy range is nominally 3 eV to 25 keV for ions and 4 eV to 30 keV for electrons, respectively. Each spectrometer consists of two half sensor heads each with 180° by 10° field-of-view, FOV, that are mounted on opposite sides of the spacecraft to form a 360° planar FOV. The out-of-plane response is roughly Gaussian with a full width, half maximum, FWHM, of about 5°. The planar FOV is within the spacecraft spin plane, which is oriented with the spin vector normal to the nominal magnetic field direction. This orientation facilitates continuous pitch angle measurements. Deflectors are used to steer the sensor FOV out of this plane by up to 10° to account for variations of the magnetic field direction during the orbit. In general, the pitch angle distribution always includes both the parallel and Anti-parallel magnetic field directions. Burst data consists of a 32 angle by 48 anergy bin array of counts. Counts are pseudo-log compressed from 16 to 8 bits onboard. The first energy step is a high voltage retrace and should be ignored. Detector anodes rotate by half an anode or 5.625° each sweep. Survey data is averaged burst data that has been despun onboard. Slow survey is averaged into a 32 angle by 48 energy array each half spin or about 2.5 s. Some blurring of the angular resolution results from the half anode rotation on alternate sweeps. Fast survey is averaged into a 64 angle by 48 energy array that maintains the angular resolution. Fast survey time resolution varies from 1/16 to 1/4 of a spin.

MMS 1 Search Coil Magnetometer (SCM) AC Magnetic Field Level 2 (L2), Burst Mode, 8192 Sample/s Data

Search Coil Magnetometer (SCM) AC Magnetic Field (8192 samples/s), Level 2, Burst Mode Data. The tri-axial Search-Coil Magnetometer with its associated preamplifier measures three-dimensional magnetic field fluctuations. The analog magnetic waveforms measured by the SCM are digitized and processed inside the Digital Signal Processor (DSP), collected and stored by the Central Instrument Data Processor (CIDP) via the Fields Central Electronics Box (CEB). Prior to launch, all SCM Flight models were calibrated by LPP team members at the National Magnetic Observatory, Chambon-la-Foret (Orleans). Once per orbit, each SCM transfer function is checked thanks to the onboard calibration signal provided by the DSP. The SCM is operated for the entire MMS orbit in survey mode. Within scientific Regions Of Interest (ROI), burst mode data are also acquired as well as high speed burst mode data. This SCM data set corresponds to the AC magnetic field waveforms in nanoTesla and in the GSE frame. The SCM instrument paper for SCM can be found at http://link.springer.com/article/10.1007/s11214-014-0096-9 and the SCM data product guide at https://lasp.colorado.edu/mms/sdc/public/datasets/fields/.

MMS 2 Magnetic Ephemeris and Coordinates (MEC) and Support (Tsyganenko 1989 model, Quiet conditions), Level 2 (L2), Burst Mode, 30 ms Data

Magnetospheric Multiscale 2 (MMS 2) spacecraft position, velocity, attitude, angular momentum vector, and magnetic ephemeris and coordinates (MEC), Level-2 science data at Burst (30 ms) time resolution. The Magnetic ephemeris data are calculated by using the Tsyganenko 1989 magnetic field model for quiet magnetospheric conditions. Many variables are included in this data product including the magnetic field measured at the spacecraft. If possible, the northern and southern hemisphere footpoints of the spacecraft are found by tracing along the magnetic field line threading through the spacecraft per the given Tsyganenko and internal magnetic field models. The northern and southern hemisphere loss cone angles are also given. The magnetic field strength at the footpoints and the minimum magnetic field strength along the field line are also calculated by using the field models. Other variables list the spacecraft L-shell, the magnetic local time, the magnetic latitude and longitude, and whether the threading field line is open, closed, etc. Rotational quaternions are provided to allow coordinate transformation from GEI into 11 other coordinate systems including BSC, GEO, GSE, GSE2000, GSE, and SM. The list of ancillary variables includes the dipole tilt angle, the Dst and Kp actvity indices, and separate flags that denote satellite eclipse by the Earth and Moon.

MMS 3 Fast Plasma Investigation, Dual Ion Spectrometer (FPI, DIS) Partial Distribution Moments, Level 2 (L2), Burst Mode, 0.15 s Data