RF Wave Detection with High-Frequency Magnetic Probes in LHD

Abstract

The study of radio frequency (RF) waves was accelerated by the start of deuterium experiments in the Large Helical Device (LHD) and the introduction of wide-band and long-time data acquisition system. The mass dependency of Ion Cyclotron Emissions (ICEs) driven by perpendicular Neutral Beam Injection (NBI) was clarified by the injection of deuterium beams. Another type of ICE by the tangential beam injection was found in the LHD. Although the details of this type of ICE have not yet been elucidated, a clear linear dependency of its frequency on the magnetic field strength divided by the mass of beam species was found. Non-localized RF waves in the Lower Hybrid Wave (LHW) frequency region were also detected during the injection of a perpendicular beam. It is shown that the frequency increases with the electron density.