Nonlinear evolution of double tearing mode with guiding magnetic field
- Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)
Nonlinear dynamic evolution of the double tearing mode (DTM) with a guiding magnetic field (B{sub y0}) is investigated by magnetohydrodynamical numerical simulation. The dynamic process of DTM depends weakly on the guiding field in the weak guiding field regime (B{sub y0{<=}}1), but is suppressed by a strong guiding field (B{sub y0}>2). During the explosive nonlinear phase, the maximum reconnection rate ({gamma}{sub max}) increases weakly with the increase of the resistivity as {gamma}{sub max{approx}{eta}}{sup 0.06} for B{sub y0{<=}}1, but for B{sub y0}>2, {gamma}{sub max} is nearly independent of the resistivity. The maximum reconnection rate in the explosive growth phase increases with increase of the initial current sheet separation. A secondary tearing instability is observed at moderate current sheet separation. A strong guiding field suppresses the formation of a secondary island. Based on the simulation results, it is found that the secondary tearing instability occurs only when the length-to-thickness aspect ratio of the reconnection region exceeds about 20.
- OSTI ID:
- 21537799
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 5; Other Information: DOI: 10.1063/1.3581064; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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