Modeling the electron heating in a compact electron cyclotron resonance ion source

Abstract

An electromagnetic particle-in-cell (PIC) model and a guiding-center particle model are developed and used to model a compact electron cyclotron resonance (ECR) plasma source. The finite-difference time-domain technique is used to model the microwave fields which excite the plasma at 2.45 GHz. The PIC technique is used to model the dynamics of the electrons in the plasma. The electromagnetic fields and the plasma dynamics are solved in a self-consistent manner. The ECR heated electrons are confined to magnetic field lines and subsequently make multiple passes through ECR regions experiencing both increases and decreases in energy. The distribution function of these energy changes is determined from the electromagnetic PIC model and used in a guiding-center particle model. The longer time scale collisional phenomenon in the plasma is modeled using this guiding-center particle model. A compact ECR plasma source used for the generation of ions for materials processing is simulated. This source has a plasma size of 3.6 cm in diameter and 3 cm in height.