Determination of the vacuum field resulting from the perturbation of a toroidally symmetric plasma

Abstract

By using the concept of a surface current, the description and calculation of the stability of modes and the plasma response function are greatly simplified. A robustly accurate and effective method is presented to determine these surface currents, considering that the perturbation is given by toroidally coupled tearing modes. A new form of the normal component of the magnetic field perturbation (B̃n), excited by a tearing mode with toroidal coupling, has been derived in terms of the solution of a hypergeometric differential equation, which is also appropriate in the large toroidal mode number (N) limit. Examples of calculations are given for different plasma cross-sectional shapes, including separatrix configurations © 1999 American Institute of Physics.