Journal article

Convolution and iterative methods applied to low frequency waves in 3D configurations

Kinetic effects have been implemented in the three-dimensional full-wave code LEMan. These allow modeling Landau damping as well as the Kinetic Alfvén Wave (KAW). Special attention has been taken on the exact computation of the parallel wave vector as it can have a strong impact on the results. Due to numerical specificities, two techniques have been used depending on the frequency domain under investigation. The damping of global modes like Toroidally-induced Alfvén Eigenmodes (TAE), which is a key issue for future reactors as they can be driven by fast ions, can then be determined. Multiple couplings are shown to lead to an increase of the damping value and thus to a stabilization of the mode. In the Ion Cyclotron Range of Frequencies (ICRF), a Large Helical Device (LHD) configuration has been investigated. For this specific case, the difference between the results obtained with an accurate determination of the parallel wave vector and the approximation kparallel=n/R has been shown to be insignificant.


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