First Plasma in the TJ-II Stellarator

The TJ-II stellarator has started during 1998 the production of stable high temperature plasma (600 eV equiv. to 7x10''6 degree centigrade K). Operation has been performed with all auxiliary systems working: cooling, power supply, vacuum, monitoring and control, diagnostics and plasma heating (300 kW of radiofrequency at 53.2 GHz). TJ-II is a low shear stellarator with major radius 1.5 m and average minor radius 0.10.2 m (1). The configuration offers high flexibility and stability to MHD phenomena. Because of this, the TJ-II concept is very attractive for reactors which aim to operate at high pressure (leading to reduction of costs in the reactor and related with the MHD stability) and steady state (stellarator configuration). In the international frame, TJ-II belongs to the Fusion Programme of EURATOM as preferential support device (funding at the level of 45% of the machine investments).Presently a similar size device is in operation in Germany (stellarator W7AS) and a larger device, with superconducting coils, started operation in Japan last April. (Author)