Propagation properties of electron cyclotron waves with helical wavefronts in magnetized plasma

Propagation properties of an optical vortex with a helical wavefront in cold uniform magnetized plasma are theoretically investigated in an electron cyclotron (EC) range of frequencies. The effects of the helical wavefront of the optical vortex on the wavefields in magnetized plasma are described. These effects are significant when the topological charge of the optical vortex is large or when the distance from the phase singularity is small. The different propagation properties are also confirmed in the propagation of Laguerre–Gaussian (LG) beams by three-dimensional simulations with the finite element method. It is found that a part of the ordinary-mode LG beam excited at the lower electron-density region is converted into the high-wavenumber extraordinary-mode LG beam at the upper hybrid resonance layer. Thus, the vortex EC wave can be a new tool to heat high-density plasma efficiently.