Analytic model of the current-voltage characteristic of a small probe in a magnetic field

Abstract

An analytic model is proposed for a small wall probe (whose dimensions perpendicular to the magnetic field are smaller than the ion Larmor radius) in a completely ionized plasma. The structure of the current collection regions is described and an analytic expression is obtained for the current-voltage characteristic of the probe. It is shown that a model with a classical diffusion coefficient gives results close to the experimental values.