Images of electrostatic lower-hybrid-wave beam propagation in tokamak plasmas using a paraxial WKB approach

A multidimensional paraxial Wentzel-Kramers-Brillouin approach is used to yield the distribution of wave potential for electrostatic lower-hybrid wave propagation in tokamak plasmas under current-drive conditions. This so-called beam tracing allows a more detailed description of wave properties than standard ray tracing. Namely, it accounts for diffraction effects, hence energy flow, in the direction perpendicular to the group velocity