Magnetic island: Difference between revisions

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However, is is possible to qualify this statement somewhat by taking into account the ratio between parallel and parpendicular transport within an island.
However, is is possible to qualify this statement somewhat by taking into account the ratio between parallel and parpendicular transport within an island.
<ref>[http://dx.doi.org/10.1088/0029-5515/33/8/I03 B.Ph. van Milligen, A.C.A.P. van Lammeren, N.J. Lopes Cardozo, F.C. Schüller, and M. Verreck, ''Gradients of electron temperature and density across m=2 islands in RTP'', Nucl. Fusion '''33''' (1993) 1119]</ref>
<ref>[http://dx.doi.org/10.1088/0029-5515/33/8/I03 B.Ph. van Milligen, A.C.A.P. van Lammeren, N.J. Lopes Cardozo, F.C. Schüller, and M. Verreck, ''Gradients of electron temperature and density across m=2 islands in RTP'', Nucl. Fusion '''33''' (1993) 1119]</ref>
The interaction of neighbouring island chains caused magnetic chaos and enhanced (anomalous) radial transport.


== References ==
== References ==
<references />
<references />

Revision as of 16:07, 18 February 2010

A magnetic island is a region of space without magnetic field sources where no field lines enter or leave. Therefore, it is bounded by a separatrix, isolating it from the rest of space. Its topology is toroidal of necessity, but its winding number can be different from 1.

In the context of magnetic confinement fusion, the basic magnetic field configuration consists of toroidally nested flux surfaces, while each flux surface is characterised by a certain value of the rotational transform or safety factor q. Magnetic islands can appear at flux surfaces with a rational value of the safety factor q = m/n. [1]

Birth

The rupture of the original topology of toroidally nested flux surfaces needed to produce the island requires the reconnection of magnetic field lines, which can only occur with finite resistivity. [2]

Transport effects

It is generally assumed that the temperature is rapidly equilibrated along the magnetic field lines inside the island, so that radial transport is effectively short-circuited across the islands, decreasing the effective size of the main plasma. [3] However, is is possible to qualify this statement somewhat by taking into account the ratio between parallel and parpendicular transport within an island. [4]

The interaction of neighbouring island chains caused magnetic chaos and enhanced (anomalous) radial transport.

References