LHD experiments started in 1998. Since then, studies to understand the intrinsic physics of net current-free plasmas have successfully proceeded. The LHD operational regime has been extended by increasing the heating capability to 23 MW of neutral beam injection (NBI), 3 MW of ion cyclotron resonance frequency (ICRF) heating, and 2.5 MW of electron cyclotron resonance heating (ECH). In addition, a new 5 MW perpendicular neutral beam injection system and a new ICRF antenna were added in FY 2010. Significant physical achievements include high beta (5.1%), high density (1.2 × 10²¹ m⁻³), and steady state operation (3200 s with 490 kW), supported by a reliable cryogenic system that has safely operated for >56,000 hours.

Global energy confinement obtained with a configuration optimized according to neoclassical theory, has proved comparable to that of tokamaks running in ELMy Hmode, exhibiting a gyro-Bohm-like property as seen in the International Stellarator Scaling (ISS95). Significant collisionality dependence (predicted by neoclassical theory) has not been observed. The optimization according to neoclassical transport theory successfully demonstrated that anomalous transport is reduced simultaneously.

Further details can be found in the Find the December issue of Stellarator News on its homepage http://www.ornl.gov/sci/fed/stelnews/