Radial profiles of (a) safety factor q, and (b) equilibrium pressure, for a large aspect ratio toroidal plasma with circular cross section. The pressure is normalized by . The radial coordinate is defined via the normalized poloidal flux . The vertical dashed line in (b) indicates the radial location of the q = 2 rational surface.
Computed resistive plasma response for the m = 2 resonant harmonic at slow plasma rotation. At finite pressure (), two regimes of rotational screening of the plasma response are identified, with opposite trends. The two dashed straight lines indicate analytic scaling laws.
Comparison of the poloidal components of the m = 2 plasma response currents near the q = 2 rational surface, at (a) a finite plasma pressure and (b) vanishing plasma pressure. The same plasma resistivity and rotation frequency are assumed, with and . Note that the range of the x-axis covers only 0.08% of the whole plasma minor radius in each case.
The real and imaginary parts of the numerically computed plasma response (dots) and the least-square fits (lines) using the analytic relation (3), for a large aspect ratio equilibrium with vanishing plasma pressure. The plasma response is scanned versus the toroidal rotation frequency . The magnetic Lundquist number for the plasma is assumed to be .
The real and imaginary parts of the numerically computed plasma response (dots) and the least-square fits (lines) using the analytic relation (3), for a large aspect ratio equilibrium with finite plasma pressure (). The plasma response is scanned versus the toroidal rotation frequency . The magnetic Lundquist number is assumed to be . The horizontal axis along the top of the figure is subject to an additional normalization factor of .
The computed TM eigenvalues plotted in the complex plane, as the magnetic Lundquist number S varies, for a finite pressure, non-rotating resistive plasma. The point, where the real growth rate bifurcates into two (complex conjugate) branches, corresponds to . The critical S value, for marginal stability of the TM, is .
Radial profiles of the poloidal Fourier harmonics for the plasma radial displacement (a, b) and perturbed parallel current density (c, d). Compared are the eigenfunctions of unstable tearing modes for the case with vanishing plasma pressure (a, c) and the case with a finite plasma pressure (b, d). The vertical dashed lines indicate the radial location of the q = 2 rational surface. The Lundquist number is for both cases.
Comparison of the computed total toroidal electromagnetic torque across the plasma column, induced by the response of a rotating resistive plasma to a static external field, produced by a coil current located at the minor radius r = 1.2a. Two plasmas, with the same Lundquist number but with different equilibrium pressures ( and 1.6, respectively), are compared. The mars-f computed torques (dots) are also compared with the analytic estimates (lines).
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