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Author: Omar E. Lopez
Requested Type: Poster
Submitted: 2018-03-01 18:42:10

Co-authors: L. Guazzotto

Contact Info:
Auburn University
224 Allison Lab
Auburn,   36849

Abstract Text:
Macroscopic flows and sheared-flows persist in typical tokamak operation and have been the subject of plenty of theoretical work. In particular, stability studies are commonly carried out through the Frieman-Rotenberg formulation [1], which casts the problem as an eigenvalue equation for a Lagrangian displacement away from the situation of equilibrium. Goedbloed has pointed out [2] that the resultant equation is a non-linear eigenvalue problem involving two self-adjoint operators and introduced an approach for finding the complex eigenfrequencies along “solutions paths”: the Spectral Web Method. In this work, we build upon an analytical solution [3] of the Grad-Shafranov-Bernoulli system for plasma equilibrium with flows, in the high-beta, high-aspect-ratio limit for a circular configuration. By following Betti’s work [4], we reduce the stability problem into a second order ODE eigenmode equation whose spectral properties are then investigated by means of the Spectral Web Method.

[1] E. Frieman and M. Rotenberg. Rev. Mod. Phys., 32:898 (1960).

[2] J. P. Goedbloed. Phys. Plasmas, 16:122110 (2009).

[3] O. E. Lopez and L. Guazzotto. Phys. Plasmas, 24:032501 (2017).

[4] R. Betti. Phys. Plasmas, 5:3615 (1998).