Disturbance of plasma environment in the vicinity of the Astrid-2 microsatellite

The presence of a satellite disturbs the ambient plasma. The charging of th e spacecraft creates a sheath around it, and the motion of the satellite cr eates a wake disturbance. This modification of the plasma environment intro duces difficulties in measuring electric fields and plasma densities using the probe technique. We present a study of the structure of the sheath and wake around the Astrid-2 microsatellite, as observed by the probes of the E MMA and LINDA instruments, Measurements with biased LINDA probes, as well a s current sweeps on the EMMA probes, show a density enhancement upstream of the satellite and a plasma depletion behind the satellite. The electric fi eld probes detect disturbances in the plasma potential on magnetic field li nes connected to the satellite.