Advanced PIC Algorithm with Adaptive Meshless Field Solver

Summary form only given. We discuss development of an advanced particle in cell (PIC) algorithm, which uses a cloud of points (meshless structure) as a reference basis to compute electromagnetic fields. The cloud of points is dynamically adapted (number of points and their locations are varied) to the field structure. The adaptation is relatively easy even for a complicated geometry, because there is no a priori given or fixed grid structure. That allows resolving boundary and current layers, sheaths, etc. simultaneously with solution to an initial problem. We apply the algorithm to model the extraction of ions from an electron cyclotron resonance ion source (ECRIS). The code calculates the steady state trajectories of the extracted ions and the electrostatic potential from Poisson´s equation self- consistently, assuming thai the space charge of the electrons from the KCRIS plasma follows a Bolt/.mann distribution. The process leads to the formation of a very thin plasma sheath, which could be just a few microns inside a device only a few centimeters in size, at the boundary between the ECRIS plasma and the ion optics. We resolve the potential drop in the sheath by adaptation of the cloud of points. Numerical simulation of ion beam extraction will be presented.