TJ-II PROJECT - A FLEXIBLE HELIAC STELLARATOR

The TJ-II device is a medium-size (R0 = 1.5 m, 〈ap〉 = 0.2 to 0.25 m, B0 = 1 T) helical-axis stellarator to be built at the CIEMAT site in Madrid. Its main characteristics are (a) potential for high-beta operation; (b) flexibility, i.e., its rotational transform can be varied over a wide range and its shear to some extent; and (c) bean-shaped plasma cross section. The latest understanding of TJ-II physics in the fields of electron cyclotron resonance heating, transport, and magnetohydrodynamics, and the engineering solutions introduced in its final design are discussed.