Electron dynamics in the vicinity of Lower Hybrid antennas

Heating and current drive in tokamaks with Lower Hybrid (LH) waves appears to generate hot spots magnetically connected to LH antennas. Correlated to these spurious patterns of heat deposition, fast electron populations are also reported experimentally. A Vlasov-Poisson (1D, 1V) model is used to address this problem. External drive by waves with appropriate spectrum to describe the physics induced by LH antennas is considered. Fast electron tails, symmetric in velocity, are shown to build-up. In the range considered in this work, the energy content of these tails is found to be proportional to the energy of the excitation LH waves.