Reconnection in Tokamaks

  1. Edward W. Hones Jr.
  1. V. K. Paré

Published Online: 19 MAR 2013

DOI: 10.1029/GM030p0341

Magnetic Reconnection in Space and Laboratory Plasmas

Magnetic Reconnection in Space and Laboratory Plasmas

How to Cite

Paré, V. K. (1984) Reconnection in Tokamaks, in Magnetic Reconnection in Space and Laboratory Plasmas (ed E. W. Hones), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM030p0341

Author Information

  1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1984

ISBN Information

Print ISBN: 9780875900582

Online ISBN: 9781118664223

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Keywords:

  • Magnetic configuration;
  • Magnetohydrodynamic (MHD);
  • Sawtooth oscillation;
  • Tokamaks;
  • Toroidal current density

Summary

In a tokamak, the superposition of an externally applied toroidal magnetic field and the field of a toroidal current induced in the plasma results in field lines that go helically around the torus. The equilibrium structure consists of toroidal surfaces nested around a toroidal magnetic axis. Often a plasma instability will cause an “island” (a separate set of nested surfaces with a helical magnetic axis) to form by reconnection. These structures usually rotate toroidally and can be observed as oscillations in local x-ray emission. Resistive MHD theory shows that one type of island can grow and - in a second reconnection - “take over” from the original magnetic axis. Sequential two-dimensional images generated from arrays of x-ray detectors show both the rotation and the growth of these islands and also the “takeover.”