The present state of investigations on stellarators in Kharkov

At present, two stellarator type fusion devices, Uragan-2M and Uragan-3M, are in operation in Kharkov. At the Uragan-3M machine, investigations of the low-density low-collisional plasma are continued. L-H-mode-like transition is studied with particular attention to the mechanisms of its formation and impact on divertor flow behaviour. For a higher density plasma, a scenario of the RF Alfv́en resonance heating in high k_|| regime is realized both with continuous and pulsed gas injection. On Uragan-2M the studies of RF wall conditioning are in progress. A new wall conditioning scheme which uses the high frequency slow wave is implemented.