Fluid Simulation: A Comparative Plasma Transport Study on Axisymmetric Cylindrical and Race-track ICP Ion Source Geometries

In the present work, we compare plasma transport phenomena among two geometrical configurations of inductively coupled plasma (ICP) under various plasma confinement magnet (PCM) arrangements and the presence of the Faraday shield (FS) conditions: 1st Axisymmetric cylindrical and 2nd Racetrack. The geometrical shapes of large fusion-grade ICP ion sources are either cylindrical or racetrack rectangular. Therefore, a systematic comparative study of plasma transport in such ICP ion source geometries will offer substantial information about their respective performance. Plasma transport studies are conducted using the COMSOL Multiphysics software, considering a constant 1MHz radio frequency (RF) power of 50 kW and a working pressure of 0.3 Pa as basic inputs. In the simulation, plasma properties, including electron density, electron temperature, and plasma potential, are assessed. In both geometrical configurations, the simulation results indicate that magnetic confinement increases plasma density by extending electron residence times and facilitating multiple ionization cycles. The Faraday shield inside the RF plasma driver boosts the efficacy of inductive coupling considerably, and it is reflected in the rise of plasma temperature and density. Compared to the case of having no Faraday shield (FS), the gradient of plasma temperature and density is relatively more uniform in either configuration. However, the Axisymmetric cylindrical configuration shows better plasma performance compared to that of the Racetrack geometry