Mercury Plasma Particle Experiments - Mercury Electron Analyzer (MEA)
Mercury Electron Analyzer (MEA1 and MEA2) of MPPE sensors onboard Mio, measures both the 3D distribution function of electrons in the solar wind and in the magnetosphere of Mercury in order to understand the structure and plasma dynamics of Mercury’s magnetosphere, Mercury-solar wind interactions, and the solar wind at Mercury’s position. MEA consists of two top-hat type toroidal electrostatic analyzers, microchannel plates (MCPs), high-voltage power supplies and power supply units. The analyzer selects energies of electrons from 3 eV/q up to 26 keV/q depending on the operation modes.
Field of view | 8 deg × 360 deg |
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Angular resolution | 22.5 deg × 11.25 deg |
Energy range | 3 eV–25,500 eV (Mercury mode) |
3 eV–3000 eV (solar wind mode) | |
Energy resolution | ΔE/E ∼ 10% (at full G-factor) |
Stepping energies and cadence | Full energy sweep with 64 contiguous energy channels every 16 or 32 times per 4 s spin |
Time resolution to obtain the full 3D velocity distribution function | Half a spin period, 2 s (using a single analyzer) |
Quarter of a spin period, 1 s (using the two analyzers) | |
Geometrical factor: MEA1 max./min. | 4.0×10−3/6.7×10−5 cm2sreV/eV |
Geometrical factor: MEA2 max./min. | 2.0×10−3/4.0×10−6 cm2sreV/eV |
Mass | 2.598 kg (for MEA1 + MEA2) +0.460 kg for their thermal shields |
Power | 2.260 W (average for MEA1 + MEA2) |
3.460 W (peak for MEA1 + MEA2) | |
1.880 W (stand-by for MEA1 + MEA2) | |
Dimensions | 177 mm×120 mm ϕ (MEA1, MEA2) |
Dimensions | 0.1 kbits/s (L-mode) |
2.5 kbits/s (M-mode) | |
11 kbits/s (H-mode) | |
after factor 3 compression for MEA1 + MEA2 |