Extension of the ray tracing for mode mixed, splitting, and dissipative wave beams in inhomogeneous magnetized plasmas

Geometrical-optics (GO) ray tracing has been widely used for modeling electron-cyclotron waves in inhomogeneous magnetized fusion plasmas. However, this reduced approach cannot calculate the wave-beam structure near the focus, and it is also inapplicable in low-density plasmas with a sheared magnetic field, where mode coupling between the two electromagnetic cold-plasma modes can occur [Phys. Plasmas 24, 122116 (2017)]. Here, we present a new beam-tracing code based on the second-order extended geometrical optics (XGO), which captures refraction, diffraction, mode coupling, and dissipation simultaneously without assuming any specific beam structure. The power splitting between the O and X modes is simulated using this new code and is found to be in good agreement with one-dimensional full-wave simulations. The focused- and defocused-beam structure is compared with that predicted by other model. Also, the profiles of the split O- and X-wave beams are discussed.