Suppression of magnetic islands by energetic ions in toroidal plasmas

Chris C. Hegna, Amitava Bhattacharjee

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4 Scopus citations

Abstract

This is a study of the effect of an energetic ion population injected from a neutral beam source on the nonlinear stability of magnetic islands. A kinetic theory is used to obtain the island current, which includes previously known modifications resulting from bootstrap currents and resistive interchanges. The island current thus obtained is used in an asymptotic treatment of the perturbed Ampère's law, which yields an evolution equation for the island width. It is shown that the island width saturates at a very small amplitude in tokamaks (with Δ′ > 0) when the energetic ion density profile peaks just outside the rational surface. Energetic ions can also be used to modify the island width in three-dimensional equilibria. It is found that in stellarator equilibria with large vacuum islands, energetic ions can be injected to reduce the widths of equilibrium islands.

Original languageEnglish (US)
Pages (from-to)1804-1814
Number of pages11
JournalPhysics of Fluids B
Volume2
Issue number8
DOIs
StatePublished - Jan 1 1990
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

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