Petra-M Full Wave Simulation of Parasitic Coupling to the Slow-Wave During ICRF Experiments on LAPD

A 3D full wave code, Petra-m¹, was used to simulate wave propagation from a single strap RF antenna in the Large Plasma Device (LAPD). Petra-M simulations allow for importing 3D CAD models of the RF antenna used in the experiments as well as experimentally measured density profiles. The experiments were carried out in a magnetized helium plasma with plasma parameters n_e ~ 10¹⁸ – 10¹⁹ m^-3, T_e ~ 1 – 10 eV and B₀ ~ 0.1 to 0.18 T. This work will compare experimental data to simulation results of the short wavelength, slow wave propagation in the plasma edge, low density region. Experiments were performed at 5-15 MHz with evidence of coupling fast-wave in the core and slow-wave in the edge were observed. With an improved solver and access to finer mesh elements, we are able to resolve the slow wave edge dynamics. Validating the simulated edge interaction with experimental results plays an important role in helping us understand interactions between RF waves and the SOL region of fusion devices.

¹S. Shiraiwa et al, EPJ Web Conf. 157, 03048 (2017).