Electron absorption of fast waves in global wave calculations

Moroz, Paul; Colestock, P.

doi:10.1088/0741-3335/33/5/002

Cited by 8 publications

(6 citation statements)

References 14 publications

(11 reference statements)

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“…These methods are therefore applicable to all orders in k Ќ , where k Ќ ϭ2/ Ќ . Previous calculations [3][4][5][6][7][8][9][10][11][12][13][14] of rf wave propagation and heating in two dimensions ͑2-D͒ have relied on either cold plasma approximations or finite Larmor radius expansions (k Ќ Ӷ1) to treat the plasma response to the rf waves. These models are therefore limited to relatively long wavelengths and low cyclotron harmonics (lр2).…”

Section: Introductionmentioning

confidence: 99%

All-orders spectral calculation of radio-frequency heating in two-dimensional toroidal plasmas

et al. 2001

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Spectral calculations of radio-frequency (rf) heating in tokamak plasmas are extended to two dimensions (2-D) by taking advantage of new computational tools for distributed memory, parallel computers. The integral form of the wave equation is solved in 2-D without any assumption regarding the smallness of the ion Larmor radius (ρ) relative to the perpendicular wavelength (λ⊥). Results are therefore applicable to all orders in k⊥ρ, where k⊥=2π/λ⊥. Previous calculations of rf wave propagation and heating in 2-D magnetized plasmas have relied on finite Larmor radius expansions (k⊥ρ≪1) and are thus limited to relatively long wavelengths. In this paper, no such assumption is made, and we consider short wavelength processes such as the excitation and absorption of ion Bernstein waves in 2-D with k⊥ρ>1. Results show that this phenomenon is far more complex than simple one-dimensional plasma models would suggest. Other applications include fully self-consistent 2-D solutions for high-harmonic fast-wave heating in spherical tokamaks. These calculations require the storage and inversion of a very large, dense matrix, but numerical convergence can be improved by writing the plasma current in the laboratory frame of reference. To accurately represent the wave spectrum in this frame, the local plasma conductivity is corrected to first order in ρ/L, where L is the equilibrium scale length. This correction is necessary to ensure accuracy in calculating the wave spectrum and hence the fraction of power absorbed by ions and electrons.

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Section: Introductionmentioning

confidence: 99%

All-orders spectral calculation of radio-frequency heating in two-dimensional toroidal plasmas

et al. 2001

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“…Global or full wave solutions to Maxwell's equations [1][2][3][4][5][6][7][8][9] in the ion cyclotron range of frequencies (ICRF) have become standard for calculating power absorption and current drive in tokamak plasmas. Such calculations are useful when geometrical optics (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…One method for dealing with these waves is to artificially damp them before the wavelength becomes too small to resolve numerically [5][6][7]. Another method is to prevent formation of the waves altogether by artificially reducing the order of the differential wave equation [1][2][3][4]. This second approach is called the 'reduced order' method.…”

Section: Introductionmentioning

confidence: 99%

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Reduced order methods for full wave ICRF calculations in tokamaks

1998

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Reduced order methods have been used extensively to eliminate ion Bernstein waves (IBWs) from full wave calculations in the ion cyclotron range of frequencies (ICRF). These reduced order methods replace higher order derivatives in the finite Larmor radius (FLR) expansion of the plasma current with algebraic terms depending on the local perpendicular wavenumber k ⊥ determined from the fourth order plasma dispersion relation. However, the dispersion relation determines only the magnitude of k ⊥ , not the direction. If k ⊥ is assumed to be perpendicular to the flux surface, energy conservation is violated near the magnetic axis. One method of dealing with this problem is to solve algebraically for the parallel electric field E , in which case the direction of k ⊥ drops out of the problem completely. Another method, which allows for the complete differential solution of E , assumes a direction for k ⊥ . Both methods are limited by assumptions. A better approach is to apply the reduced order algorithm to the ion FLR current alone, while treating the electron current differentially. Since the direction of k ⊥ enters only through electron terms, this method resolves the ambiguity in the direction of k ⊥ while still suppressing the IBW, which originates in the ion current. Comparison with the simpler models suggests that it is necessary to include the differential electron current for an accurate description of direct electron heating and fast wave current drive near the ion second harmonic.

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“…The transport formulas were used in the CRONOS transport code along with the WAVE code for the plasma heating profile from the Fast Wave Ion Cyclotron heating [Moroz and Colestock (1991)] used to drive the Tore Supra plasma. The results showed a good predictive performance as shown in Fig.…”

mentioning

confidence: 99%

Electron Temperature Gradient Driven Turbulence

Jenko¹

2012

Turbulent Transport in Magnetized Plasmas

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Electron absorption of fast waves in global wave calculations

Cited by 8 publications

References 14 publications

All-orders spectral calculation of radio-frequency heating in two-dimensional toroidal plasmas

All-orders spectral calculation of radio-frequency heating in two-dimensional toroidal plasmas

Reduced order methods for full wave ICRF calculations in tokamaks

Electron Temperature Gradient Driven Turbulence

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