1. SST- Solid State Telescope ESA - Electrostatic Analyzer Science Measurement and Operational Requirements

2. SST Science Requirements The SST shall perform measurements of the tailward-moving current disruption boundary speed using finite gyroradius technique The SST shall measure the time-of-arrival of superthermal ions and electrons (30-300 keV, at 10s resolution or better) during injections, and ascertain the Rx onset time (P1, P2). Radiation Belts (secondary science) – measure high energy electron fluxes into 6RE Dayside (tertiary science) – upstream ions, magnetopause and magnetosheath fluxes

3. ESA Science Requirements The ESA shall obtain moments of the ion and electron distributions with one spin time resolution for interprobe timing studies The ESA shall measure differences in velocity and ion pressure between probes to estimate the scale size of transport structures and the size and strength of flow vortices and pressure gradients The ESA shall obtain measurements of ion and electron distributions with one spin time resolution to identify sources of free energy and evidence of acceleration processes

4. SST Performance Requirements The SST shall contribute to the determination of particle moments (for the determination of onset time). The SST shall measure energetic ions and electrons over an energy range of 30-300keV for ions and 30-100keV for electrons found in the tail region from 9-30 RE. The SST energy sampling resolution, dE/E, shall be better than 30% for ions and electrons. The SST shall be capable of measuring differential energy flux in the range from: 10^2 to 5x10^6 for ions; 10^3-10^7 for electrons (keV/cm2-s –st- keV) whilst providing adequate counts within a 10 second interval. (exact values TBD) The SST shall measure Sunward, Duskward, and Dawnward fluxes @ 10 second resolution. SST calibration shall ensure <10% absolute relative flux uncertainty over the ranges defined above

5. ESA Performance Requirements The ESA shall measure energetic ions and electrons over an energy range of 0.01-30keV for ions and electrons. The ESA shall supply the medium energy ion and electron distributions for combination with SST measurements to compute plasma particle moments. The ESA energy sampling resolution, dE/E, shall be better than 25% FWHM for ions and electrons. The total ESA geometric factors (cm2-sr-eV/eV) shall be approximately 0.01 for ions and 0.005 for electrons. ESA calibration shall ensure <10% absolute relative flux uncertainty (not including statistical uncertainty) over the ranges defined above The ESA shall have a 180 degree elevation field of view with a minimum of eight contiguous angle sectors. The ESA will produce measurement of particle distributions over the entire 4  steradian field of view in one spin period

6. Performance Requirements Energy Range / Resolution Anticipated Flux levels (Count Rate) Time Resolution Angular Resolution Partial moments (E>~30 keV)

7. Energy Range

8. SST Energy Range / Resolution 1.Primary science requirements– –Electrons – 30-100 keV (goal: 15keV - ~1MeV) –Ions – 30-300 keV (goal: 20 keV- 6 MeV) –Resolution: dE/E 30% 2.Radiation belts: –Need to attain science goals (without saturation) 3.Bowshock, Magnetosheath and Upstream: –Primary requirements are sufficient.

9. ESA Energy Range/ Resolution 1.Primary science requirements– –Electrons: 0.01 -30 keV –Ions: 0.01 – 30 keV (goal: 40 keV) –Resolution: dE/E: 30% 2.Radiation belts: –Low priority (likely large background) 3.Bowshock, Magnetosheath and Upstream: –Primary requirements are sufficient.

10. SST Anticipated EFlux 1.Primary science- Large dynamic range of flux requires multiple geometric factors 2.Radiation belts- Instrument will typically be saturated by lower energt particles. Might be able to recover higher energy measurements by raising thresholds. This needs more study! 3.Dayside- Satisfied by primary science requirements (albeit large geometric factors are desirable)

11. Expected Energy Flux Probability distribution of log(Eflux(30 keV)) (electrons)

12. ESA Anticipated EFlux 1.Primary science- Single geometric factor is adequate. (Eflux<10^9) 2.Radiation belts- Instrument will typically be affected by penetrating particles. Not of interest. 3.Dayside- Solar Wind ion measurement requires attenuated geometric factor and finer energy steps. Magnetosheath requires no changes.

13. SST and ESA Time resolution: Constrained primarily by telemetry limitations. (Partial) Moments will provide 1 spin (3 second) time resolution.

14. SST Angular Resolution Phi angle resolution: 22.5 degrees. (primarily limited by telemetry) Elevation resolution: ~30-45 degrees. (primarily limited by number of sensors)

15. ESA Angular Resolution 1.Primary Science –Phi angle resolution: 22.5 degrees. –Elevation resolution: 22.5 degrees. 2.Radiation Belt 3.Dayside (Solar Wind) –5.6 x 5.6 degree resolution –dE/E = 25%

16. Partial Moments SSTs provides high energy partial moments at one spin resolution. ESA provide low energy portion of partial moments. Total moments combined on the ground.

17. Operational Requirements Mass Power Telemetry Radiation Thermal Requirements