Magnetic island: Difference between revisions

Magnetic island (view source)

87 bytes removed , 18 February 2010

no edit summary

4,424

edits

@@ Line 1: / Line 1: @@
-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|separatrix]], isolating it from the rest of space.
+A magnetic island is a closed magnetic flux tube (cf. [[Flux surface]]), bounded by a [[Separatrix|separatrix]], isolating it from the rest of space.
-Its topology is toroidal of necessity, but its [[:Wikipedia:Winding number|winding number]] can be different from 1.
+Its topology is toroidal.
 In the context of magnetic confinement fusion, the basic magnetic field configuration consists of toroidally nested [[Flux surface|flux surfaces]], while each flux surface is characterised by a certain value of the [[Magnetic shear|rotational transform]] or safety factor ''q''. Magnetic islands can appear at flux surfaces with a rational value of the safety factor ''q = m/n''.
 <ref>[http://dx.doi.org/10.1051/anphys:2004001 J.H. Misguich, J.-D. Reuss, D. Constantinescu, G. Steinbrecher, M. Vlad, F. Spineanu, B. Weyssow, R. Balescu, ''Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines'', Ann. Phys. Fr. '''28''' (2003) 1]</ref>
+Subsidiary islands can appear within an island.
-== Birth ==
+== Island 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.