Solvable self-similar model of the sausage instability in a resistive Z-pinch. Interim report
A solvable model is developed for the linearized sausage mode within the context of resistive MHD. The model is based on the assumption that the fluid motion of the plasma is self-similar, as well as several assumptions pertinent to the long-wavelength limit. The perturbations to the magnetic field are not assumed to be self-similar, but rather are calculated. Effects arising from time dependences of the equilibrium, e.g., current rising as T, alpha ohmic heating, and time variation of the pinch radius, are included in the analysis. The formalism appears to provide a good representation of those modes that involve coherent sausage distortion of the entire cross section of the pinch, but excludes modes that are localized radially, and higher radial eigenmodes. For this and other reasons, it is expected that the model underestimates the maximum instability growth rates, but is reasonable for global sausage modes. The net effect of resistivity and time variation of the equilibrium is to decrease the growth rate if alpha somewhat< 1, but never by more than a fact of about two. The effect is to increase the growth rate if alpha somewhat>1.
- Research Organization:
- Naval Research Lab., Washington, DC (USA)
- OSTI ID:
- 5115998
- Report Number(s):
- AD-A-213137/3/XAB; NRL-MR--6549
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700107* -- Fusion Energy-- Plasma Research-- Instabilities
DOCUMENT TYPES
EIGENVECTORS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PINCH DEVICES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PROGRESS REPORT
SAUSAGE INSTABILITY
THERMONUCLEAR DEVICES
TIME DEPENDENCE
VARIATIONS