MHD Stabilization by the Magnetic Hill at a Small Rotational Transform
- Nuclear Fusion Institute, Russian Research Centre Kurchatov Institute, pl. Kurchatova 1, Moscow, 123182 (Russian Federation)
The effect of very small rotational transform on the plasma stability in three-dimensional closed magnetic configurations with closed magnetic field lines, stabilized by the magnetic hill (i.e., by the plasma compressibility), is considered using ideal MHD theory. It is shown that, for infinitely small values of the rotational transform, the Suydam-Mercier criterion predicts the onset of acoustic instability with a finite growth rate, provided that the Bernstein-Kadomtsev criterion is satisfied. Consequently, for a vanishingly small rotational transform, the limiting transition from the Suydam-Mercier criterion to the Bernstein-Kadomtsev criterion is impossible. Taking into account the finite Larmor radius allows this limiting transition to be made. The Bernstein-Kadomtsev criterion ensures MHD stability at rotational transform values below a certain critical value determined by the ratio of the ion Larmor radius to the plasma minor radius. Under experimental conditions, this critical value is larger than that expected to be produced by the actual magnetic perturbations.
- OSTI ID:
- 20717493
- Journal Information:
- Plasma Physics Reports, Vol. 31, Issue 2; Other Information: Translated from Fizika Plazmy, ISSN 0367-2921, 31, 133-145 (No. 2, 2005); DOI: 10.1134/1.1866594; (c) 2005 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); TN:; ISSN 1063-780X
- Country of Publication:
- United States
- Language:
- English
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