Volt-ampere characteristics of a spherical cooled probe in the transition mode

Electrostatic probes are often used under conditions where the mean free path of charged particles is much larger than the Debye radius and much smaller than the probe size. Such conditions correspond to the transition from the collisionless mode to the diffusion mode. Here, the volt-ampere characteristics of a cooled spherical probe in a three-component weakly ionized plasma with frozen ionization and recombination processes are analyzed in the transition range. It is shown that in the case of strongly cooled probes, the saturation ion current is essentially different from the value based on the continuum theory.