Flattening of the tokamak current profile by a fast magnetic reconnection with implications for the solar corona

Abstract

During tokamak disruptions the profile of the net parallel current is observed to flatten on a time scale that is so fast that it must be due to a fast magnetic reconnection. After a fast magnetic reconnection has broken magnetic surfaces, a single magnetic field line covers an entire volume and not just a magnetic surface. The current profile, given by $K\equiv {\mu }_0{j}_{||}/B$, relaxes to a constant within that volume by Alfvén waves propagating along the chaotic magnetic field lines. The time scale for this relaxation determines the commonly observed disruption phenomena of a current spike and a sudden drop in the plasma internal inductance. An efficient method for studying this relaxation is derived, which allows a better understanding of the information encoded in the current spike and the associated sudden drop in the plasma internal inductance. Implications for coronal heating are also discussed.

4 pages, no figures

References in corpus (2)

• Runaway dynamics in the DT phase of ITER operations in the presence of massive material injection
• Runaway Electron Seed Formation at Reactor-Relevant Temperature

Cited by in corpus (7)

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• The rapid destruction of toroidal magnetic surfaces
• Example of exponentially enhanced magnetic reconnection driven by a spatially-bounded and laminar ideal flow
• Magnetic field evolution and reconnection in low resistivity plasmas
• The interaction of the ITER first wall with magnetic perturbations
• Local analysis of fast magnetic reconnection