Spheromak Formation and Current Sustainment Using a Repetitively Pulsed Source

摘要

By repeated injection of magnetic helicity (K = 2ψΨ) on time-scales short compared with the dissipation time (τ_(inj) ＜＜ τ_K), it is possible to produce toroidal currents relevant to POP-level experiments. Here we discuss an effective injection rate, K_(eff) = 2ψ_(gun)I_(gun)L due to the expansion of a series of current sheets and their subsequent reconnection to form spheromaks and compression into a copper flux-conserving chamber. The benefits of repeated injection are that the usual limits to current amplification can be exceeded, and an efficient quasi-steady sustainment scenario is possible (within minimum impact on confinement). A new experiment designed to address the physics of pulsed formation and sustainment is described.