Optimized profiles for improved confinement and stability in the DIII-D tokamak
1994; IOP Publishing; Volume: 36; Issue: 12B Linguagem: Inglês
10.1088/0741-3335/36/12b/019
ISSN1361-6587
AutoresT. S. Taylor, H. St. John, A. D. Turnbull,
Tópico(s)Particle accelerators and beam dynamics
Resumoview Abstract Citations (94) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Coronal Heating by the Resonant Absorption of Alfven Waves: Importance of the Global Mode and Scaling Laws Steinolfson, Richard S. ; Davila, Joseph M. Abstract Numerical simulations of the MHD equations for a fully compressible, low-beta, resistive plasma are used to study the resonance absorption process for the heating of coronal active region loops. Comparisons with more approximate analytic models show that the major predictions of the analytic theories are, to a large extent, confirmed by the numerical computations. The simulations demonstrate that the dissipation occurs primarily in a thin resonance layer. Some of the analytically predicted features verified by the simulations are (a) the position of the resonance layer within the initial inhomogeneity; (b) the importance of the global mode for a large range of loop densities; (c) the dependence of the resonance layer thickness and the steady-state heating rate on the dissipation coefficient; and (d) the time required for the resonance layer to form. In contrast with some previous analytic and simulation results, the time for the loop to reach a steady state is found to be the phase-mixing time rather than a dissipation time. This disagreement is shown to result from neglect of the existence of the global mode in some of the earlier analyses. The resonant absorption process is also shown to behave similar to a classical driven harmonic oscillator. Publication: The Astrophysical Journal Pub Date: September 1993 DOI: 10.1086/173169 Bibcode: 1993ApJ...415..354S Keywords: Absorption Spectra; Magnetohydrodynamic Waves; Plasma Heating; Plasma Resonance; Solar Corona; Coronal Loops; Scaling Laws; Solar Physics; MAGNETOHYDRODYNAMICS: MHD; SUN: CORONA full text sources ADS |
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