Skip to Main content Skip to Navigation
Journal articles

Ray-tracing and Fokker–Planck modelling of the effect of plasma current on the propagation and absorption of lower hybrid waves

Abstract : Waves at a frequency close to the lower hybrid (LH) resonance are widely used in tokamaks for non-inductive current drive. Modelling of LH waves is usually carried out by combining a Ray-tracing (RT) code for computing the LH waves propagation to a solver of the Fokker–Planck (FP) equation which calculates an electron distribution function self-consistently with the waves absorption. The DELPHINE code has been developed along this approach with accurate treatment of the magnetic equilibrium and the fast electrons dynamics in momentum space. Using this code, the influence of the plasma current on the LH waves propagation and absorption is investigated in detail. High plasma current is found to broaden the absorbed LH spectrum towards high phase velocities, thus increasing the current drive efficiency of the waves. The shape of the current density profile also has an impact on the propagation of the waves and the resulting power deposition. In discharges where the current profile is dominated by LH current drive (LHCD), this dependence leads to the auto-regulation of the LHCD via the current density profile. The RT/FP technique reproduces at least qualitatively some of the experimental trends, though inconsistencies still remain. Perspectives for improving the relevance of the modelling are discussed.
Document type :
Journal articles
Complete list of metadatas

Cited literature [40 references]  Display  Hide  Download

https://hal-cea.archives-ouvertes.fr/cea-01715161
Contributor : Frédéric Imbeaux <>
Submitted on : Thursday, February 22, 2018 - 2:09:53 PM
Last modification on : Monday, October 1, 2018 - 4:03:03 PM
Long-term archiving on: : Wednesday, May 23, 2018 - 1:28:14 PM

File

RAY_IP_2005.pdf
Publisher files allowed on an open archive

Identifiers

Collections

Citation

Frédéric Imbeaux, Y. Peysson. Ray-tracing and Fokker–Planck modelling of the effect of plasma current on the propagation and absorption of lower hybrid waves. Plasma Physics and Controlled Fusion, IOP Publishing, 2005, 47, pp.2041 - 2065. ⟨10.1088/0741-3335/47/11/012⟩. ⟨cea-01715161⟩

Share

Metrics

Record views

128

Files downloads

305