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.

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.

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.

THEMIS-E: Electrostatic Analyzers (ESA): Electron/Ion Ground-Calculated Energy Fluxes (5eV - 25 keV for Ions and 6eV - 30 KeV for Electrons) and Moments (density, velocity, pressure, and temperature). The satellite has 2 modes Fast and Slow survey and 3 data types: FULL, REDUCED and BURST. FULL: 88 angles x 32 energies, time resolution of 128 spins(395 seconds) in slow survey and 32 spins(98 seconds) in fast survey. REDUCED: spin time resolution(3 sec) but angles averaged into 1 angular spectra x 32 energies in slow survey or 6 angular spectra(90 degree x 90 degree window) x 32 energies in fast survey. BURST: 88 angles x 32 energies and spin time resolution(3 sec) but only available sporadically and for short duration. Note that angular resolution affects moments since they are obtained integrating over the mode-specific angular distribution. These moments are processed on the ground. They should be regarded as approximations but will improve in quality as our processing routines are improved over the course of the mission to account for additional sources of variance.

THEMIS-D: Electrostatic Analyzers (ESA): Electron/Ion Ground-Calculated Energy Fluxes (5eV - 25 keV for Ions and 6eV - 30 KeV for Electrons) and Moments (density, velocity, pressure, and temperature). The satellite has 2 modes Fast and Slow survey and 3 data types: FULL, REDUCED and BURST. FULL: 88 angles x 32 energies, time resolution of 128 spins(395 seconds) in slow survey and 32 spins(98 seconds) in fast survey. REDUCED: spin time resolution(3 sec) but angles averaged into 1 angular spectra x 32 energies in slow survey or 6 angular spectra(90 degree x 90 degree window) x 32 energies in fast survey. BURST: 88 angles x 32 energies and spin time resolution(3 sec) but only available sporadically and for short duration. Note that angular resolution affects moments since they are obtained integrating over the mode-specific angular distribution. These moments are processed on the ground. They should be regarded as approximations but will improve in quality as our processing routines are improved over the course of the mission to account for additional sources of variance.

THEMIS-C: Electrostatic Analyzers (ESA): Electron/Ion Ground-Calculated Energy Fluxes (5eV - 25 keV for Ions and 6eV - 30 KeV for Electrons) and Moments (density, velocity, pressure, and temperature). The satellite has 2 modes Fast and Slow survey and 3 data types: FULL, REDUCED and BURST. FULL: 88 angles x 32 energies, time resolution of 128 spins(395 seconds) in slow survey and 32 spins(98 seconds) in fast survey. REDUCED: spin time resolution(3 sec) but angles averaged into 1 angular spectra x 32 energies in slow survey or 6 angular spectra(90 degree x 90 degree window) x 32 energies in fast survey. BURST: 88 angles x 32 energies and spin time resolution(3 sec) but only available sporadically and for short duration. Note that angular resolution affects moments since they are obtained integrating over the mode-specific angular distribution. These moments are processed on the ground. They should be regarded as approximations but will improve in quality as our processing routines are improved over the course of the mission to account for additional sources of variance.

THEMIS-A: Electrostatic Analyzers (ESA): Electron/Ion Ground-Calculated Energy Fluxes (5eV - 25 keV for Ions and 6eV - 30 KeV for Electrons) and Moments (density, velocity, pressure, and temperature). The satellite has 2 modes Fast and Slow survey and 3 data types: FULL, REDUCED and BURST. FULL: 88 angles x 32 energies, time resolution of 128 spins(395 seconds) in slow survey and 32 spins(98 seconds) in fast survey. REDUCED: spin time resolution(3 sec) but angles averaged into 1 angular spectra x 32 energies in slow survey or 6 angular spectra(90 degree x 90 degree window) x 32 energies in fast survey. BURST: 88 angles x 32 energies and spin time resolution(3 sec) but only available sporadically and for short duration. Note that angular resolution affects moments since they are obtained integrating over the mode-specific angular distribution. These moments are processed on the ground. They should be regarded as approximations but will improve in quality as our processing routines are improved over the course of the mission to account for additional sources of variance.

THEMIS-B: Electrostatic Analyzers (ESA): Electron/Ion Ground-Calculated Energy Fluxes (5eV - 25 keV for Ions and 6eV - 30 KeV for Electrons) and Moments (density, velocity, pressure, and temperature). The satellite has 2 modes Fast and Slow survey and 3 data types: FULL, REDUCED and BURST. FULL: 88 angles x 32 energies, time resolution of 128 spins(395 seconds) in slow survey and 32 spins(98 seconds) in fast survey. REDUCED: spin time resolution(3 sec) but angles averaged into 1 angular spectra x 32 energies in slow survey or 6 angular spectra(90 degree x 90 degree window) x 32 energies in fast survey. BURST: 88 angles x 32 energies and spin time resolution(3 sec) but only available sporadically and for short duration. Note that angular resolution affects moments since they are obtained integrating over the mode-specific angular distribution. These moments are processed on the ground. They should be regarded as approximations but will improve in quality as our processing routines are improved over the course of the mission to account for additional sources of variance.

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.

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.