2D Equilibrium Study of Mirror Field Impact on FRC Magnetic and Density Profiles

A new software named Grushenka [1] has been developed for fully two-dimensional equilibrium analysis of FRC (Field-Reversed Configuration [2]) plasmas in a short time between experiments. It allows analysis with limited input --wall magnetic field, plasma dimensions, and average density. It can also analyze non-FRC plasmas. Compared to previously used quasi-one-dimensional models, Grushenka offers significant advantages, including the ability to account for external magnetic field curvature and incorporate the effects of the scrape-off layer.

In this study, we investigate the effects of mirror magnetic field strength on equilibrium structures using Grushenka. Previous studies have shown that, as the mirror field strength is reduced, the produced plasma tends to deviate from FRC relaxation. Grushenka allows the mirror field strength to be set as an input parameter, making it suitable for such analysis. Here, magnetic field structures and electron density profiles obtained from Grushenka are compared with experimental measurements under varying mirror field strengths. Systematic changes in field and density profiles are observed, reflecting the influence of mirror confinement on FRC formation.