Investigation of tearing instability using GeFi particle simulation model

Journal Article · Thu Dec 15 04:00:00 EST 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3662435· OSTI ID:22047111

Wang, X Y; Lin, Y; Lu, X; Kong, W ^[1]; Chen, L ^[2]

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1. Physics Department, Auburn University, Auburn, Alabama 36849-5311 (United States)
2. Department of Physics and Astronomy, University of California at Irvine, California, 92697 (United States)

The gyrokinetic (GK) electron and fully kinetic ion (GeFi) simulation model of Lin et al.[Plasmas Phys. Controlled Fusion 53, 054013 (2011)] has been thoroughly benchmarked and validated for a two-dimensional (2D) Harris current sheet with a finite guide field. First, a gyrokinetic eigenmode theory for the collisionless tearing mode in the small Larmor radius limit is presented. The linear eigenmode structure and growth rate of the tearing mode obtained from the GeFi simulation are benchmarked against those from the GK eigenmode analysis in the limit of L>>{rho}{sub i}>{rho}{sub e}, where L is the current sheet half-width, {rho}{sub i} is ion Larmor radius, and {rho}{sub e} is electron Larmor radius. Second, to valid the GeFi model, both the linear and nonlinear tearing instabilities obtained from the GeFi simulations are compared with the Darwin particle-in-cell (PIC) simulation. The validation of the GeFi model for laboratory and space plasmas is also discussed. Meanwhile, the GeFi simulation is carried out to investigate both the linear and nonlinear tearing instabilities for cases with a broad range of L and guide magnetic field B{sub G}. It is found that in a wide current sheet with L > 4.5{rho}{sub eK}, the nonlinear saturation level of the island half-width is w{sub s}{approx_equal} 3{rho}{sub eK}, where {rho}{sub eK} = {rho}{sub e}B{sub 0}/B{sub x0}, B{sub 0} is the strength of the asymptotic magnetic field, and B{sub x0} is the antiparallel field. On the other hand, in a thin current sheet with L < 2.5{rho}{sub eK}, w{sub s}{approx_equal} 2.2 L. In addition, a high frequency electrostatic drift mode is found to coexist with the tearing mode.

• OSTI ID: 22047111
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 12 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASYMPTOTIC SOLUTIONS
EIGENFUNCTIONS
EIGENVALUES
ELECTRONS
IONS
LARMOR RADIUS
MAGNETIC FIELDS
NONLINEAR PROBLEMS
PLASMA
PLASMA DRIFT
PLASMA SIMULATION
PLASMA WAVES
TEARING INSTABILITY
TWO-DIMENSIONAL CALCULATIONS