Beta-Value Limits and MHD 6.High-Beta Relaxed Configurations

Abstract

Advanced fusion such as D-³He requires an ultra-high-β plasma. The field-reversed configuration (FRC) plasma is a candidate because of its intrinsic ultra-high-β: <β>≈1. The FRC can be produced by merging spheromaks with counter helicities. This result strongly implies that the FRC represents a new relaxed state, which is not a Taylor's state. Recently, the two-fluid relaxation theory has been developed to describe a relaxed state with finite pressure gradient such as FRC. The theory calls for an Alfvenic flow in the relaxed state. In order to drive such a fast flow, preliminary experiments have been performed to which external electrodes or non-neutral plasmas are applied.