Radiation pressure of radio frequency waves on plasma turbulence

It has previously been shown that radio frequency (RF) electromagnetic waves are partially scattered when propagating through density fluctuations in the edge region of fusion devices. The scattering affects the flow of wave energy to the plasma core. Conversely, the radiation pressure due to the RF waves can affect plasma turbulence. We determine the radiation force on incoherent fluctuations using Kirchhoff's tangent plane approximation and Fresnel-type scattering analysis. The force on a coherent filamentary structure is determined using the Maxwell stress tensor. The filament is assumed to be cylindrical with its axis aligned along the ambient magnetic field. The two approaches share similar physical outcomes. For waves in the electron cyclotron range of frequencies, filaments with densities higher than the background density are pulled in towards the RF source, while those with lower densities are pushed away. The radiation force is large enough to impact the motion of filaments, and could possibly be observed in experiments. This suggests the possibility of utilizing RF waves to modify some aspects of edge turbulence.