Nonlinear tearing mode interactions and mode locking in reversedfield pinches
Abstract
The nonlinear interaction of a set of tearing instabilities and plasma flow is studied in a cylindrical plasma. An analytic theory of mode locking is developed, which includes the effects of the localized electromagnetic torques, plasma inertia, and crossfield viscosity. The calculation is specialized for the case of mode locking on the Madison Symmetric Torus (MST) reversedfield pinch [R. N. Dexter {ital et} {ital al}., Fusion Technol. {bold 19}, 131 (1991)]. In MST plasmas, a set of {ital m}=1 tearing instabilities become phase locked and form a toroidally localized, rotating magnetic disturbance. An evolution equation for the phase velocity of this magnetic disturbance is derived that accounts for two types of electromagnetic torques. The external torques describe the interaction of the tearing modes with static magnetic perturbations located outside the plasma region. The interior torques describe the nonlinear interaction of three tearing modes that satisfy a wave number resonance condition. For conditions typical of MST, the internal torques dominate the external torques, which suggest the nonlinear interaction of tearing instabilities play a prominent role in the momentum degradation and mode locking. {copyright} {ital 1996 American Institute of Physics.}
 Authors:

 Departments of Nuclear Engineering and Engineering Physics and Physics, University of Wisconsin, Madison, Wisconsin 537061687 (United States)
 Publication Date:
 OSTI Identifier:
 397523
 DOE Contract Number:
 FG0285ER53212; FG0286ER53218
 Resource Type:
 Journal Article
 Journal Name:
 Physics of Plasmas
 Additional Journal Information:
 Journal Volume: 3; Journal Issue: 12; Other Information: PBD: Dec 1996
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION; REVERSEFIELD PINCH; TEARING INSTABILITY; MODE LOCKING; PLASMA MACROINSTABILITIES; MAGNETOHYDRODYNAMICS; PHASE VELOCITY
Citation Formats
Hegna, C C. Nonlinear tearing mode interactions and mode locking in reversedfield pinches. United States: N. p., 1996.
Web. doi:10.1063/1.872033.
Hegna, C C. Nonlinear tearing mode interactions and mode locking in reversedfield pinches. United States. doi:10.1063/1.872033.
Hegna, C C. Sun .
"Nonlinear tearing mode interactions and mode locking in reversedfield pinches". United States. doi:10.1063/1.872033.
@article{osti_397523,
title = {Nonlinear tearing mode interactions and mode locking in reversedfield pinches},
author = {Hegna, C C},
abstractNote = {The nonlinear interaction of a set of tearing instabilities and plasma flow is studied in a cylindrical plasma. An analytic theory of mode locking is developed, which includes the effects of the localized electromagnetic torques, plasma inertia, and crossfield viscosity. The calculation is specialized for the case of mode locking on the Madison Symmetric Torus (MST) reversedfield pinch [R. N. Dexter {ital et} {ital al}., Fusion Technol. {bold 19}, 131 (1991)]. In MST plasmas, a set of {ital m}=1 tearing instabilities become phase locked and form a toroidally localized, rotating magnetic disturbance. An evolution equation for the phase velocity of this magnetic disturbance is derived that accounts for two types of electromagnetic torques. The external torques describe the interaction of the tearing modes with static magnetic perturbations located outside the plasma region. The interior torques describe the nonlinear interaction of three tearing modes that satisfy a wave number resonance condition. For conditions typical of MST, the internal torques dominate the external torques, which suggest the nonlinear interaction of tearing instabilities play a prominent role in the momentum degradation and mode locking. {copyright} {ital 1996 American Institute of Physics.}},
doi = {10.1063/1.872033},
journal = {Physics of Plasmas},
number = 12,
volume = 3,
place = {United States},
year = {1996},
month = {12}
}