The bootstrap current in small rotating magnetic islands
- Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, D-85748 Garching(Germany)
- Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL (United Kingdom)
The bootstrap current in small magnetic islands of neoclassical tearing modes is studied with guiding center particle simulations including pitch angle scattering. A model for a rotating island and its electric field is used and a new approximation to the electric potential in small islands is derived. Islands with sizes of the order of the ion banana orbit width are studied by means of a two-step model, which allows to treat both ions and electrons kinetically. The bootstrap current in such small islands is found to depend strongly on the direction of rotation of the island. The bootstrap current in small islands rotating in the ion diamagnetic direction is strongly diminished, similarly to what happens in big islands. In small islands rotating in the electron diamagnetic direction, on the contrary, the bootstrap current is almost completely preserved, implying a reduced neoclassical drive of the island growth.
- OSTI ID:
- 21282109
- Journal Information:
- Physics of Plasmas, Vol. 16, Issue 9; Other Information: DOI: 10.1063/1.3234252; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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