Speaker
Dr
Stuart Hudson
(Princeton Plasma Physics Laboratory)
Description
The nature of ideal-MHD equilibria in three-dimensional geometry is profoundly affected by resonant surfaces, which beget a non-analytic dependence of the equilibrium on the boundary. Furthermore, non-physical currents arise in equilibria with continuously-nested magnetic surfaces and smooth pressure and rotational-transform profiles.
We demonstrate that three-dimensional, ideal-MHD equilibria with nested surfaces and delta-function current-densities that produce a discontinuous rotational-transform are well defined and can be computed both perturbatively and using fully-nonlinear equilibrium calculations.
The results are of direct practical importance: we predict that resonant magnetic perturbations penetrate past the rational surface (i.e. ``shielding'' is incomplete, even in purely ideal-MHD) and that the perturbation is amplified by plasma pressure, increasingly so as stability limits are approached.
Country or International Organization | USA |
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Paper Number | TH/1-1 |
Primary author
Dr
Stuart Hudson
(Princeton Plasma Physics Laboratory)
Co-author
Dr
Joaquim Loizu
(Max Planck Institut for Plasma Physic)