Analysis of the Validity of the Asymptotic Techniques in the Lower Hybrid Wave Equation Solution For Reactor Applications
- Associazione Euratom-ENEA sulla Fusione, C.P. 65 - I-00044 - Frascati, Rome (Italy)
Conscious that the wave propagation of the LH in tokamak plasmas can be correctly described only with a full wave approach based on full numerical techniques or on a semi-analytical approach, in this paper we solve asymptotically the LH wave equation by the WKB approximation for the first two orders of the expansion parameter, obtaining the phase at the lowest and the amplitude at the next order. The non-linear PDE for the phase will be solved in a pseudo-toroidal geometry (circular and concentric magnetic surfaces) by the method of characteristics as described. The associated system of ODE'S for the position and the wave-number is obtained and analytically solved by choosing an appropriate expansion parameter. The quasi-linear PDE for the WKB amplitude is also analytically solved, allowing the reconstruction of the wave electric field inside the plasma. The solution will be also solved numerically, and a comparison with the analytical solution will be addressed. A discussion of the validity of the WKB approximation based on the obtained results will be also given.
- OSTI ID:
- 20895133
- Journal Information:
- AIP Conference Proceedings, Vol. 871, Issue 1; Conference: Joint Varenna-Lausanne international workshop on theory of fusion plasmas, Varenna (Italy), 28 Aug - 1 Sep 2006; Other Information: DOI: 10.1063/1.2404560; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Paraxial WKB Method Applied to the Lower Hybrid Wave Propagation
Numerical and asymptotic studies of complex flow dynamics. Annual report 1993