Firstorder finiteLarmorradius fluid modeling of tearing and relaxation in a plasma pinch
Abstract
Drift and Hall effects on magnetic tearing, island evolution, and relaxation in pinch configurations are investigated using a nonreduced firstorder finiteLarmorradius (FLR) fluid model with the nonideal magnetohydrodynamics (MHD) with rotation, open discussion (NIMROD) code [C.R. Sovinec and J. R. King, J. Comput. Phys. 229, 5803 (2010)]. An unexpected result with a uniform pressure profile is a drift effect that reduces the growth rate when the ion sound gyroradius ({rho}{sub s}) is smaller than the tearinglayer width. This drift is present only with warmion FLR modeling, and analytics show that it arises from {nabla}B and poloidal curvature represented in the Braginskii gyroviscous stress. Nonlinear singlehelicity computations with experimentally relevant {rho}{sub s} values show that the warmion gyroviscous effects reduce saturatedisland widths. Computations with multiple nonlinearly interacting tearing fluctuations find that m = 1 coreresonantfluctuation amplitudes are reduced by a factor of two relative to singlefluid modeling by the warmion effects. These reduced coreresonantfluctuation amplitudes compare favorably to edge coil measurements in the Madison Symmetric Torus (MST) reversedfield pinch [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. The computations demonstrate that fluctuations induce both MHD and Halldynamo emfs during relaxation events. The presence of a Halldynamo emf implies amore »
 Authors:

 Department of Physics, University of WisconsinMadison, 1150 University Ave., Madison, Wisconsin 53706 (United States)
 Department of EngineeringPhysics, University of WisconsinMadison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States)
 Publication Date:
 OSTI Identifier:
 22072375
 Resource Type:
 Journal Article
 Journal Name:
 Physics of Plasmas
 Additional Journal Information:
 Journal Volume: 19; Journal Issue: 5; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070664X
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; CALCULATION METHODS; FLOW MODELS; FLUCTUATIONS; IONS; LARMOR RADIUS; MAGNETOHYDRODYNAMICS; MST DEVICE; NIMROD; NONLINEAR PROBLEMS; PLASMA; PLASMA SIMULATION; RELAXATION; REVERSEFIELD PINCH; REYNOLDS NUMBER; ROTATION; SOUND WAVES; STRESSES
Citation Formats
King, J R, TechX Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303, Sovinec, C R, and Mirnov, V V. Firstorder finiteLarmorradius fluid modeling of tearing and relaxation in a plasma pinch. United States: N. p., 2012.
Web. doi:10.1063/1.3695346.
King, J R, TechX Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303, Sovinec, C R, & Mirnov, V V. Firstorder finiteLarmorradius fluid modeling of tearing and relaxation in a plasma pinch. United States. doi:10.1063/1.3695346.
King, J R, TechX Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303, Sovinec, C R, and Mirnov, V V. Tue .
"Firstorder finiteLarmorradius fluid modeling of tearing and relaxation in a plasma pinch". United States. doi:10.1063/1.3695346.
@article{osti_22072375,
title = {Firstorder finiteLarmorradius fluid modeling of tearing and relaxation in a plasma pinch},
author = {King, J R and TechX Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303 and Sovinec, C R and Mirnov, V V},
abstractNote = {Drift and Hall effects on magnetic tearing, island evolution, and relaxation in pinch configurations are investigated using a nonreduced firstorder finiteLarmorradius (FLR) fluid model with the nonideal magnetohydrodynamics (MHD) with rotation, open discussion (NIMROD) code [C.R. Sovinec and J. R. King, J. Comput. Phys. 229, 5803 (2010)]. An unexpected result with a uniform pressure profile is a drift effect that reduces the growth rate when the ion sound gyroradius ({rho}{sub s}) is smaller than the tearinglayer width. This drift is present only with warmion FLR modeling, and analytics show that it arises from {nabla}B and poloidal curvature represented in the Braginskii gyroviscous stress. Nonlinear singlehelicity computations with experimentally relevant {rho}{sub s} values show that the warmion gyroviscous effects reduce saturatedisland widths. Computations with multiple nonlinearly interacting tearing fluctuations find that m = 1 coreresonantfluctuation amplitudes are reduced by a factor of two relative to singlefluid modeling by the warmion effects. These reduced coreresonantfluctuation amplitudes compare favorably to edge coil measurements in the Madison Symmetric Torus (MST) reversedfield pinch [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. The computations demonstrate that fluctuations induce both MHD and Halldynamo emfs during relaxation events. The presence of a Halldynamo emf implies a fluctuationinduced Maxwell stress, and the simulation results show net transport of parallel momentum. The computed magnitude of force densities from the Maxwell and competing Reynolds stresses, and changes in the parallel flow profile, are qualitatively and semiquantitatively similar to measurements during relaxation in MST.},
doi = {10.1063/1.3695346},
journal = {Physics of Plasmas},
issn = {1070664X},
number = 5,
volume = 19,
place = {United States},
year = {2012},
month = {5}
}