The effect of the electron drift velocity on the saturation current in a spherical probe

The effect of the electron drift velocity on the saturation current of a spherical probe has been determined for a diffusion regime, when it is necessary to take into account the electron sink effect. It is shown that for sufficiently large electric fields $Е$, $еЕа\ge kТ_е$ ($a$ is the probe radius and $Т_е$ is the electron temperature) the actual saturation current may notably exceed its value calculated for the case of zero drift velocity.