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Title: Gyrokinetic-ion drift-kinetic-electron simulation of the (m = 2, n = 1) cylindrical tearing mode

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. University of Colorado at Boulder, Boulder, Colorado 80309, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1240304
Grant/Contract Number:
AC02-05CH11231; FC02-08ER54971; FG02-08ER54987; SC0008801
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Related Information: CHORUS Timestamp: 2018-03-29 14:50:45; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Chen, Y., Chowdhury, J., Maksimovic, N., Parker, S. E., and Wan, W. Gyrokinetic-ion drift-kinetic-electron simulation of the (m = 2, n = 1) cylindrical tearing mode. United States: N. p., 2016. Web. doi:10.1063/1.4943105.
Chen, Y., Chowdhury, J., Maksimovic, N., Parker, S. E., & Wan, W. Gyrokinetic-ion drift-kinetic-electron simulation of the (m = 2, n = 1) cylindrical tearing mode. United States. doi:10.1063/1.4943105.
Chen, Y., Chowdhury, J., Maksimovic, N., Parker, S. E., and Wan, W. Fri . "Gyrokinetic-ion drift-kinetic-electron simulation of the (m = 2, n = 1) cylindrical tearing mode". United States. doi:10.1063/1.4943105.
@article{osti_1240304,
title = {Gyrokinetic-ion drift-kinetic-electron simulation of the (m = 2, n = 1) cylindrical tearing mode},
author = {Chen, Y. and Chowdhury, J. and Maksimovic, N. and Parker, S. E. and Wan, W.},
abstractNote = {},
doi = {10.1063/1.4943105},
journal = {Physics of Plasmas},
number = 5,
volume = 23,
place = {United States},
year = {Fri Mar 04 00:00:00 EST 2016},
month = {Fri Mar 04 00:00:00 EST 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4943105

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  • New field solvers are developed in the gyrokinetic code GEM [Chen and Parker, J. Comput. Phys. 220, 839 (2007)] to simulate low-n modes. A novel discretization is developed for the ion polarization term in the gyrokinetic vorticity equation. An eigenmode analysis with finite Larmor radius effects is developed to study the linear resistive tearing mode. The mode growth rate is shown to scale with resistivity as γ ∼ η{sup 1∕3}, the same as the semi-collisional regime in previous kinetic treatments [Drake and Lee, Phys. Fluids 20, 1341 (1977)]. Tearing mode simulations with gyrokinetic ions are verified with the eigenmode calculation.
  • Cited by 3
  • The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current sheet with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic electron and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-electron mass ratio m i/m e. In contrast to the fully kinetic PIC simulation scheme, the fast electron cyclotron motion and plasma oscillations are systematically removed in the GeFi model, and hence one can employ the realistic m i/m e. The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location wheremore » $$\vec{k}$$• $$\vec{B}$$ =0, consistent with previous analytical and simulation studies. Here, $$\vec{B}$$ is the equilibrium magnetic field and $$\vec{k}$$ is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at $$\vec{k}$$ •$$\vec{B}$$ ≠0. Additionally, the simulation results indicate that varying m i/m e, the current sheet width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.« less
  • The performance (β N ≈ 3, q 95 ≈ 4.4, f BS ≈ 0.5, H 89 > 2) of hybrid scenario plasmas in DIII-D is limited by m/n = 2/1 tearing modes. Unlike conventional plasmas, the linear dependence scaling of the global beta for onset of the instability with normalized local ion gyroradius ρ i * is modified as the n = 1 ideal kink beta limit is approached, suggesting that small island neoclassical tearing mode (NTM) threshold physics does not impose the dominant criterion for NTM stability. The hybrid scenario tends to go unstable just at or below themore » no wall n = 1 ideal kink beta limit of about 4l. Experimentally 4l i decreases with beta as 4l i ≈ 5.7 β N -1/2. Thus the 'ceiling' in beta due to coupling of tearing to the ideal kink comes down as beta is increased. Scaling of the tearing unstable beta that combines both NTM threshold physics and a pole in Δ'r due to coupling to the ideal kink is presented« less