Linear and nonlinear dynamics of Alfvhn eigenmodes in tokamaks
نویسنده
چکیده
Linear and nonlinear dynamics of various toroidicity induced global Alfvin eigenmodes is investigated by means of an initial value numerical code. The code uses the reduced magnetohydrodynamic (MHD) model expanded to the third order in the inverse aspect ratio parameter E (E = a/R,, with a the minor radius of the plasma column and R, the major radius of the vacuum chamber). Nonlinear saturation is shown to occur due to the excitation of a perturbation to the nonlinear mode structure, which dissipates energy on very short scales. In particular, the nonlinear saturation of the Toroidal Alfven Eigenmodes (TAE) and of the Resistive Periodic Shear Alfvin Eigenmodes (RPSAE) due to MHD nonlinearities is investigated and compared with analytical predictions.
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