HIGH-VOLTAGE ELECTRON COLLECTION BY A SPHERICAL SATELLITE

The numerical solution to the cold electron flow equations is presente d for the region surrounding an ionospheric satellite at high positive potential. The momentum, continuity, and Poisson equations are solved simultaneously for satellite potentials of 1000, 10,000, 30,000, and 100,000 kT (kT = 0.17 eV). The electron velocity vectors in the sheath region are presented. The electron current density to the satellite s urface is also reported. Electrons impact the satellite surface with a verage velocity vectors having angles of incidence (relative to the su rface normal) that increase from the satellite's magnetic pole to equa tor. A toroidal flow develops in the vicinity of the magnetic equator and expands away from the satellite surface as the surface potential i s increased. The current density to the satellite surface increases wi th increasing satellite potential and decreases with increasing polar angle.