Comparison between measured and simulated features of current collection by the tethered satellite

Summary form only given, as follows. The reflight of the tethered satellite system has revealed an intriguing set of plasma processes affecting collection of electrons by a conducting body biased at a positive potential. Currents greatly in excess of that predicted from the Parker-Murphy theory have been measured, but the scaling of the current with the bias potential (/spl Phi//sub 0/) is found to be approximately the same as predicted by the theory for sufficiently large value of /spl Phi//sub 0/. Three-dimensional particle-in-cell simulations of current collection by a conducting spherical body in a magnetized plasma reveals similar behaviors of the current collection. The geometrical aspects of the current flow in the plasma contributing to the collection of electrons by the body and the structure of the sheath will be discussed.