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HL-2A is a tokamak based on the original ASDEX components (vacuum vessel and magnets). The pumping system, power supply, auxiliary heating, energy storage equipmemt and diagnostics were constructed by SWIP. According to the national program to develop nuclear fusion in China, the construction of HL-2A was approved in 1998 by government as the largest tokamak in China during the period of National Ninth Five-years Program (1995-2000).
HL-2A was put into operation in 2002. The parameters of HL-2A are summarized in table 1. The auxiliary heating with total power of about 10 MW is being developed (as shown in table 2)
HL-2A uses an air-core transformer. 3 motor generators with total energy storage up to 1.3GJ feed the coils and auxiliary heating via power supply (PS). Normally, vaccum vessel is baked at the beginning of an experimental campaign. During discharges, siliconization and other wall conditioning techniques make significant improvement on the plasma performance and decrease of the impurities. The pulsed gas puffing, in which the timing and amount of gas for each pulse are precisely controlled, operates as normal fueling. A pellet injection which is able to inject up to 8 pellets is used. The molecular beam injection (MBI), which was first used on the HL-1M, is presently carried to investigate the fueling efficiency among different types of fueling.
More
than 30 diagnostics have been installed, such as HCN interferometer, Thomson
scattering and ECE, etc. Some new diagnostics (MSE and CXRS) are being
developed. Modeling and data acquisition, storage and analyses are progressing
steadly. The first divertor configuration was achieved in 2003 experimental
season, and new results on MBI was obtained also.
As the first divertor tokamak in China, broad fundamental studies are involved in program, such as research on the plasma confinement improvement, divertor, SOL, transport, MHD, energetic particles, facing plasma materials, etc. Relevant engineering and techniques will be improved, such as operation and control, plasma heating, refueling, wall conditioning, diagnostics, modeling and others. Further topics related to ITER will be explored on HL-2A.
HL-2A modification has been started since 2004. It aims at a medium elongated plasma shape with certain triangularity, and more effective and flexible divertor. The detailed design is being made by dedicated group in SWIP. Large support has been gotten from government.
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