An Ion Temperature Sensitive End Effect In Cylinderical Langmuir Probe Response At Ionospheric Satellite Conditions

Computations and experiments are presented for an end effect which can dominate the ion current response of long, cylindrical Langmuir probes in high speed, collisionfree flows. The end effect, which takes the form of an increase in ion current when the probe is aligned with the flow direction, depends strongly on the plasma properties and flow speed, and can be large even for very long probes when the speed ratio is large and the probe radius small compared with the Debye length. Experimental data are compared with theory, and some apparently contradictory results reported in the literature are reconciled in terms of the end effect. (Author).