Particle-in-cell simulations of wave propagation in front of a lower hybrid grill

Particle-in-cell (PIC) codes can be applied to model wave coupling, propagation and absorption. The electrostatic PIC code XPDP2 has been used to analyse the edge plasma and the formation of fast electrons in front of the LH launcher. PIC codes take into account the kinetic and nonlinear effects, which are in some LHCD cases important, e.g., fast electron generation in edge plasmas and possible parametric instabilities. These effects are not included in linear coupling codes like SWAN. Particle-in-cell (PIC) codes are based on solving the equations of motion for the charged particles and the Maxwell equations for the fields. The particles move freely in the phase space and interact with the elelectric and magnetic fields on the grid. The motion of the charged particles generates current and charge densities acting as source terms in the Maxwell equations. Consequently, the fields and the particle motion are solved self-consistently. The disadvantage is the fairly high noise level, which can be slightly by increasing the number of particles. In this work, an electromagnetic particle-in-cell code OOPIC has been used to model wave launching from a 32 waveguide LH grill similar to the grill in Tore Supra and JET.