A Köhn et al 2008 Plasma Phys. Control. Fusion 50 085018 doi:10.1088/0741-3335/50/8/085018
A Köhn1, Á Cappa2, E Holzhauer1, F Castejón2, Á Fernández2 and U Stroth1
Show affiliationsA finite-difference time-domain code is used to obtain the full-wave solution of the O–X mode conversion process for typical parameters of the TJ-II stellarator in a cylindrical geometry. This reduction of the complicated stellarator geometry to a cylindrical geometry is chosen since the conversion process occurs only over a limited radial plasma volume. In the calculations, Gaussian antenna beams are studied with the option of different beam waists in the poloidal and toroidal direction. Optimum conversion efficiency is found if the wavefront of the incident antenna beam is matched to the local curvature of the O–X conversion layer. Finally, the code is used to calculate the complete O–X–B conversion process into a Bernstein wave.
52.55.Hc Stellarators, torsatrons, heliacs, bumpy tori, and other toroidal confinement devices
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides
Issue 8 (August 2008)
Received 26 March 2008, in final form 23 May 2008
Published 27 June 2008
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