Neutral beam injection heating on field-reversed configuration plasma decompressed through axial translation

摘要

The power deposition of neutral beam injection (NBI) on translated field-reversed configuration (FRC) plasma has been investigated. A certain level of electron heating effect was observed in the slowly decaying phase of the decompressed FRC, leading to a hollow electron temperature profile. Numerical calculation of beam trajectories has shown that about 50% of the injected NB power is absorbed by the plasma electron inside the separatrix with a hollow deposition profile similar to the observed electron temperature profile. The estimated absorbed NB power of 120 kW will be enough to bring the change in electron temperature, since the electron conduction and radiation loss was estimated to be ～100 kW.