Laboratory observations of electron temperature in the wake of a sphere in a streaming plasma

A parametric study was performed of electron-temperature variation in the wake of a conducting sphere in a streaming plasma. The flow conditions were varied as follows: the ambient electron temperatures in the range from 850 to 2450 K; the ambient electron densities in the range from 0.0005 to 0.00007 per cu cm; and body potentials relative to plasma potential in the range from +1.7 to -2.8 V for an ion-beam energy of approximately 4 eV. Electron-temperature enhancements were observed which ranged up to 200 per cent above ambient in the nearest proximity of the body surface. The magnitude of the enhancement depends upon the ambient density, temperature, and body potential.