Investigating Microwave Driven Plasmas Utilizing the MOOSE Framework

Simulations to investigate the under and over density regimes of microwave driven plasmas have been conducted utilizing the MOOSE [Multiphysics Object-Oriented Simulation Environment] framework. Emphasis was placed on the transition region of these regimes where the plasma frequency approaches the drive frequency, also known as the critical density. Electric fields were obtained utilizing MOOSE's internal electromagnetic solver, while the plasma dynamics were solved by MOOSE's multi-fluid plasma application, Zapdos. One-way and two-way coupling between the solvers were incorporated to investigate the degree of feedback between the field propagation, power deposition, and plasma parameters (such as electron density, electron temperature, collision frequency, etc.) in 2D axisymmetric and 3D simulations. The plasma is driven by supplying a microwave signal (~2.45 GHz) into an axisymmetric ceramic above a vacuum chamber, with the power supplied into ceramic ranging between 25 - 125W. For gas chemistry, focus was placed on argon at mid-pressure ranges (~0.1 Torr to a few Torr).