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Your search keyword '"Vallejos, Pablo"' showing total 2 results
Start Over Author "Vallejos, Pablo" Topic finite element method
2 results on '"Vallejos, Pablo"'

1. Iterative method for including parallel dispersion for RF waves in two-dimensional axisymmetric finite element models.

Author

Zaar, Björn, Johnson, Thomas, and Vallejos, Pablo

Subjects
FINITE element method, CYCLOTRON resonance, ION acoustic waves, DISPERSION (Chemistry), RADIO frequency, OCEAN waves
Abstract

Modelling the propagation and dissipation of RF waves in the ion cyclotron range of frequencies is challenging due to the presence of spatial dispersion. In this work, we are presenting an iterative scheme that includes dispersive effects in all tensor elements in 2D axisymmetry. The proposed method is implemented in the existing full wave solver FEMIC and applied to two fast wave heating scenarios, one with an ITER-like plasma and the other with an AUG-like plasma, in order to evaluate the importance of parallel dispersion in the two different cases. It was found that parallel dispersion is of marginal importance in ITER when using dipole phasing, but has larger impact on the power deposition profiles in AUG, due to up-down asymmetric heating. Furthermore, it is shown that the described iterative method can account for mode conversion to the ion cyclotron wave. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Iterative addition of finite Larmor radius effects to finite element models using wavelet decomposition

Author

Vallejos, Pablo

Subjects
ion-Bernstein waves, mode conversion, Other Electrical Engineering, Electronic Engineering, Information Engineering, Physics::Plasma Physics, Morlet wavelets, Physics::Space Physics, finite element method, ion cyclotron resonance heating, Annan elektroteknik och elektronik
Abstract

Modeling the propagation and damping of electromagnetic waves in a hot magnetized plasma is difficult due to spatial dispersion. In such media, the dielectric response becomes non-local and the wave equation an integro-differential equation. In the application of RF heating and current drive in tokamak plasmas, the finite Larmor radius (FLR) causes spatial dispersion, which gives rise to physical phenomena such as higher harmonic ion cyclotron damping and mode conversion to electrostatic waves. In this paper, a new numerical method based on an iterative wavelet finite element scheme is presented, which is suitable for adding non-local effects to the wave equation by iterations. To verify the method, we apply it to a case of one-dimensional fast wave heating at the second harmonic ion cyclotron resonance, and study mode conversion to ion Bernstein waves in a toroidal plasma. Comparison with a local (truncated FLR) model showed good agreement in general. The observed difference is in the damping of the ion Bernstein wave, where the proposed method predicts stronger damping on the ion Bernstein wave.

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