FDTD Simulation of O-X Mode Conversion Process in Non-uniform Magnetized Plasma

TL;DR

This paper investigates the O-X mode conversion process in non-uniform magnetized plasma using FDTD simulations, highlighting the importance of incident angle optimization for efficient EBW excitation.

Contribution

It introduces a finite difference time-domain simulation approach to analyze how incident angle affects mode conversion in non-uniform plasmas, providing insights for plasma heating applications.

Findings

Optimal incident angle exists for maximum wave propagation efficiency.

Strong electric field enhancement occurs near the upper hybrid resonance.

Deviations from optimal angle cause wave attenuation due to evanescent regions.

Abstract

Electron Bernstein Waves (EBWs) are electrostatic waves than can propagate in overdense plasmas without density cutoff, making them suitable for high density plasma heating. Since EBWs cannot be directly launched from vacuum, mode conversion processes such as O-X-B conversion are required. In this study, the O-X mode conversion process is investigated using the finite difference time-domain (FDTD) method in a magnetized plasma with non-uniform density. In particular, the dependence of mode conversion characteristics on the incident angle of the injected wave is studied. The results show that an optimal incident angle exists at which the wave propagates without significant attenuation and strong electric field enhancement is observed near the upper hybrid resonance (UHR) layer. When the incident angle deviates from this optimal angle, an evanescent region appears, resulting in attenuation of the wave. These results demonstrate that angular optimization is essential for efficient wave propagation toward the UHR region and EBW excitation.