Full-wave modeling of the O-X mode conversion in the Pegasus Toroidal Experiment

TL;DR

This paper models the O-X mode conversion in the Pegasus Toroidal Experiment using a 2D full-wave code, highlighting the impact of plasma density profiles and plasma displacements on conversion efficiency for EBW heating.

Contribution

It provides a detailed full-wave simulation of O-X mode conversion in Pegasus, emphasizing the influence of plasma density shape and robustness to plasma displacements.

Findings

Density profile shape significantly affects conversion efficiency.

Conversion efficiency is resilient to vertical plasma displacements up to ±10 cm.

Full-wave modeling aids in optimizing EBW heating systems.

Abstract

The ordinary-extraordinary (O-X) mode conversion is modeled with the aid of a 2D full-wave code in the Pegasus Toroidal Experiment as a function of the launch angles. It is shown how the shape of the plasma density profile in front of the antenna can significantly influence the mode conversion efficiency and, thus, the generation of electron Bernstein waves (EBW). It is therefore desirable to control the density profile in front of the antenna for successful operation of an EBW heating and current drive system. On the other hand, the conversion efficiency is shown to be resilient to vertical displacements of the plasma as large as \pm 10 cm.