Aperture effects on charged particles in a magnetic field

Abstract

In this paper we present investigations of two kinds of aperture effects on charged particles in the presence of a magnetic field. The first is an experimental study of the plasma potential profiles in front of an aperture. Plasma potential is measured with emissive probes. The interaction between the plasma and the solid wall of the aperture results in a nonuniform potential profile. Our experiments show that suitable aperture biasing can smooth the electric field in front of the aperture. The second is the transmission of electrons through a finite thickness aperture. The experimental results of the latter are compared to results of a single particle orbit model. It is shown that transmission measurements can be used to estimate the electron perpendicular energy in the magnetic field..