Picked-up protons near Mars: Phobos observations
Abstract
The measurements carried out by the plasma spectrometer, ASPERA, onboard the PHOBOS-2 spacecraft show that protons, originating in the extended hydrogen corona of Mars, were observed at altitudes ≤7500 km. The cyclotron instability of these pickup ions appears to generate Alfven waves observed by the MAGMA magnetometer. Analysis of the plasma data shows that weak pitch-angle diffusion of a ring-distribution of pickup protons occurs. The altitude profiles of pickup proton fluxes and number densities of the parent hydrogen atoms are derived.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- October 1991
- DOI:
- 10.1029/91GL02082
- Bibcode:
- 1991GeoRL..18.1805B
- Keywords:
-
- Magnetohydrodynamic Waves;
- Mars Atmosphere;
- Phobos;
- Proton Beams;
- Satellite Observation;
- Space Plasmas;
- Lyman Alpha Radiation;
- Magnetohydrodynamic Stability;
- Magnetometers;
- Mass Spectrometers;
- Spectrograms;
- Vertical Distribution;
- Magnetospheric Physics: Solar wind interactions with unmagnetized bodies;
- Planetology: Solid Surface Planets and Satellites: Interactions with particles and fields;
- Space Plasma Physics: Wave-particle interactions