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Title: Numerical magnetohydrodynamic simulations of expanding flux ropes: Influence of boundary driving

The expansion dynamics of a magnetized, current-carrying plasma arch is studied by means of time-dependent ideal MHD simulations. Initial conditions model the setup used in recent laboratory experiments that in turn simulate coronal loops [J. Tenfelde et al., Phys. Plasmas 19, 072513 (2012); E. V. Stenson and P. M. Bellan, Plasma Phys. Controlled Fusion 54, 124017 (2012)]. Boundary conditions of the electric field at the “lower” boundary, intersected by the arch, are chosen such that poloidal magnetic flux is injected into the domain, either localized at the arch footpoints themselves or halfway between them. These conditions are motivated by the tangential electric field expected to exist in the laboratory experiments due to the external circuit that drives the plasma current. The boundary driving is found to systematically enhance the expansion velocity of the plasma arch. While perturbations at the arch footpoints also deform its legs and create characteristic elongated segments, a perturbation between the footpoints tends to push the entire structure upwards, retaining an ellipsoidal shape.
Authors:
;  [1] ;  [2]
  1. Theoretische Physik I, Ruhr-Universität Bochum, Bochum (Germany)
  2. Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)
Publication Date:
OSTI Identifier:
22227923
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 7; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DISTURBANCES; ELECTRIC CURRENTS; ELECTRIC FIELDS; MAGNETIC FIELD CONFIGURATIONS; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; NUMERICAL ANALYSIS; PLASMA; PLASMA SIMULATION; TIME DEPENDENCE