Some Considerations and Techniques for the Predictive Simulation of Global Instabilities in Tokamaks
Authors: S.C. Jardin
Abstract:
This is a write‐up of a lecture given at the Fourth ITER International Summer School held at the IFS, U. Texas in June 2010. A simple rigid plasma model is used to show that axisymmetric plasma instabilities (in two‐dimensions) will occur on a resistive timescale and do not depend on the plasma mass. This is the justification for ignoring the inertial term in two‐dimensional studies of plasma shape control and vertical stability. In three dimensions, it is not normally possible to ignore the inertial terms when computing plasma instabilities. This results in a stiff system of equations (with multiple timescales) in which the driving terms causing plasma instabilities are small compared with the stable compressive terms. Techniques are described for implicit time integration and for representing the vector fields in a way to facilitate obtaining accurate solutions for plasma instabilities when a strong background magnetic field is present.
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Submitted to: Fusison Science and Technology (September 2010)
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Download PPPL-4547 (pdf 245 KB 12 pp)
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