Analysis of the spectral width and validation of the LHBEAM code
- FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands)
- Max-Planck-Institut fuer Plasmaphysik, IPP, D-85748 Garching (Germany)
- Associaton Euratom-CEA, CEA/DSM/DRFC, CEA-Cadarache, 13108, Saint Paul lez Durance (France)
A crucial point of the theoretical study of lower-hybrid (LH) current drive in a tokamak plasma is the spectral gap problem, i.e., the fact that the parallel (to the magnetic field) refractive index spectrum generated at the plasma edge does not appear to be wide enough for the interaction of the wave with a large number of electrons. This is in contrast with experimental observations. Diffraction is one of the mechanisms that can lead to the observed wave spectrum broadening and solve the spectral gap problem. For this reason, a new beam tracing code, LHBEAM, has been developed in order to study the diffraction effects on the propagation and the absorption of LH waves in tokamak plasma. In this work, the parallel spectral width is addressed on the basis of the beam tracing approximate solution. A preliminary implementation of the results is done in LHBEAM which has been also compared with the ray tracing code C3PO for the assessment of the trajectory of the central ray and of the evolution of the parallel refractive index on this ray.
- OSTI ID:
- 21251743
- Journal Information:
- AIP Conference Proceedings, Vol. 1069, Issue 1; Conference: Joint Varenna-Lausanne international workshop on theory of fusion plasmas, Varenna (Italy), 25-29 Aug 2008; Other Information: DOI: 10.1063/1.3033710; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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