HT-7 tokamak is a super-conducting machine, including the main machine, cryogenic, power supply, vacuum, ICRH, LHCD, diagnostics, control and data acquisition systems. Its construction was accomplished in May 1994 based on redesigning its predecessor, the T-7 super-conducting tokamak from Russia, with T-7 torus structure completely changed to improve the accessibility. In December 1994, the engineering test was finished and experiments have been conducted on the HT-7 super-conducting tokamak since then.

The experiments on the HT-7 super-conducting tokamak are aimed to study the plasmas in steady-state and relevant techniques. The device is operated in two campaigns (about 4 months) every year. The discharges last normally several seconds, with the record longest discharges being 10.7 seconds. The discharges with electron temperature higher than 10 million Kelvin have been achieved for nearly 4 seconds. The maximum plasma current and electron density are 255kA and 6.5´ 1019/m3 at toroidal field of 2 Tesla. Total input power, including ohmic, ICRF and LHW, exceeds 1 MW. Full current drive by LHW has been achieved for longer than 6 seconds. Maximum current ramp-up of 90kA by LHW has been obtained. Both electron and ion heating and confinement improvement have been achieved in IBW heated plasma. ICRF wall conditioning, boronization and siliconization have been routinely applied to reduce the impurity level, control the recycling and get plasma in high performance. ICRF has also been used for pre-ionization, reduce the break-down loop voltage and control the rate of plasma current ramp-up very effectively. Real-time feed back control, distributed data acquisition, power supply, PFC material and various diagnostic techniques are developed to improve the plasma control and better physical understanding.