Viability of COMSOL as a Simulation Software for Doppler Backscattering in Turbulent Plasmas

The use of COMSOL to simulate Doppler Backscattering (DBS) is evaluated for both X- and O-mode. Models range from a simple linear density ramp to profiles derived from tokamak data. We examine beam profile evolution, received-power response versus fluctuation amplitude, polarization effects, and Bragg-selected k response. The simulations recover the expected P ⁣∝ ⁣dn^2 scaling and k-selection near the cutoff. Furthermore, beam characteristics such as the minimum waist location were scanned to determine the ideal location to maximize the response of the back-scattered beam. These results demonstrate that COMSOL is a viable tool for modeling DBS in plasmas.