Electrostatic Particle-in-Cell Model for a Lower Hybrid Grill

摘要

In recent lower hybrid (LH) current drive experiments, generation of hot spots211u001eand impurities in the grill region have been observed. A possible explanation is 211u001ethe parasitic absorption of the LH power in front of the grill. In parasitic 211u001eabsorption, the short-wavelength part of the lower hybrid spectrum can resonantly 211u001einteract with the cold edge electrons. In this work the absorption of the LH 211u001ewaves and the generation of fast electrons near the waveguide mouth is 211u001einvestigated with a new tool in this context: particle-in-cell (PIC) simulations. 211u001eThe advantage of this new method is that the electric field is calculated self-211u001econsistenly. The PIC simulations also provide the key parameters for the hot spot 211u001eproblem: the absorbed power, the radial deposition profiles and the absorption 211u001elength.