Spatial Structure of Low-Frequency Hall-MHD Wave Propagation in a Field-Reversed Configuration Plasma

A linear Hall-MHD simulation code is developed to investigate the spatial structure of two-dimensional wave propagation excited in a field-reversed configuration (FRC) equilibrium plasma. A low-frequency oscillating magnetic field at 160 kHz is externally applied by a ring coil installed concentrically with the device axis in the open-field region. The generated toroidal magnetic field propagates primarily along magnetic field lines at a phase velocity comparable to that of shear Alfvén waves. Due to the Hall effect, toroidal magnetic fluctuations penetrate into the closed-field region near the separatrix over a distance on the order of the ion skin depth. In the core region, where magnetic fluctuations vanish, ion density oscillations become dominant.