The computation of resistive MHD instabilities in axisymmetric toroidal plasmas
An optimal formulation of the resistive MHD stability eigenmode equations was developed for the purpose of computational studies. In order to accurately calculate resistive instabilities for resistivities in the range of fusion reactors, it is essential to overcome the problem of numerical errors caused by terms in the eigenmode equations associated with the fast magnetosonic wave. This type of numerical error is referred to as spectral pollution. A specific formulation fo the linearized resistive MHD eigenmode equations was carefully chosen on the basis of minimizing the numerical error due to spectral pollution by accurately resolving the continuum spectrum of the ideal MHD operator. The effective technique used for eliminating spectral pollution is not limited to only working in the 1d cylindrical limit. The formulation reduces the resistive MHD stability equations into three second order coupled equations in a manner such that one of the three equations recovers the identical formulation of the NOVA code in the ideal limit. The nonvariational approach being used was already successfully applied to the linearized ideal MHD eigenmode equations in the NOVA code. Two stability codes were developed in order to implement the formulation. The NOVA-RC stability code solves the linearized resistive MHD eigenmode equations for 1d cylindrical equilibria. The NOVA-R stability code solves the linearized resistive MHD eigenmode equations for a given axisymmetric toroidal plasma equilibrium with noncircular flux surfaces. Results from both codes are presented in order to establish their credibility. The eigenfunctions are represented by a Fourier expansion and cubic B-spline finite elements. The full set of linearized resistive MHD equations are solved everywhere in the plasma, rather than using asymptotic matching between ideal and resistive regions.
- Research Organization:
- Princeton Univ., NJ (USA)
- OSTI ID:
- 5903978
- Resource Relation:
- Other Information: Ph.D. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PLASMA INSTABILITY
EQUATIONS
TOROIDAL PINCH DEVICES
EIGENVECTORS
FINITE ELEMENT METHOD
FOURIER ANALYSIS
MAGNETOACOUSTIC WAVES
THEORETICAL DATA
CLOSED PLASMA DEVICES
DATA
HYDROMAGNETIC WAVES
INFORMATION
INSTABILITY
NUMERICAL DATA
NUMERICAL SOLUTION
PINCH DEVICES
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities