First experiments on RF plasma production at relatively low magnetic fields in the LHD

The results of the first experimental series to produce a plasma using the radio frequency discharge (RF) above the ion cyclotron frequency at relatively low magnetic fields (0.5–0.6 T) in the Large Helical Device (LHD) are presented 1.43 MW of RF power produced target plasma with density up to 6 × 10¹⁸ m⁻³ to deuterium. Tangential NBI application into such a plasma increases plasma parameters. Electron temperatures up to ≈0.9 keV and densities up to ≈2.4 × 10¹⁹ m⁻³ had been achieved, and the maximum value of <β_dia> was 2.6%. These experiments open possibilities for new regimes of LHD operation which are also interested to W7-X.