Tokamak is considered as the most promising experimental setup for achieving controllable nuclear fusion requirements.The parameter βN is an important parameter for tokamak devices:high βN benefits not only to plasma fusion but also to the enhancement of fusion reaction efficiency and the facilitation of steady-state operation.The HL-2A tokamak device has achieved stable plasma with βN exceeding than 2.5 through neutral beam injection heating,and transiently reached βN = 3.05,with a normalized density(ne,l/ne,G)of about 0.6,stored energy(WE)of around 46 kJ,and confinement improvement factor(H98)of about 1.65.In this work,the integrated simulation platform OMFIT is used to analyze the plasma at βN = 2.83 and βN = 3.05,and the obtained WE,ne,l/ne,G,H98,βN,etc.are consistent with the experimental parameters.The bootstrap current(fBS)can reach to 45%and 46%.At both of the above moments,there are ion temperature double transport barrier(DTB)generated by the coexistence of internal transport barrier(ITB)and edge transport barrier(ETB),while high βN is usually related to DTB.In addition,the formation of ion temperature ITB in the HL-2A device is further analyzed,which is attributed to the dominance of turbulent transport in plasma transport,the suppression of turbulent transport in the core by fast ions and E×B shear,and the resulting improvement in confinement,thereby ultimately leading to the formation of ion temperature ITB.The ITB of ion temperature and the ETB of H-mode synergistically contribute to the creation of high βN plasma.
关键词
HL-2A/高βN/OMFIT集成模拟/快离子/内部运垒
Key words
HL-2A/High-βN/OMFIT integrated simulation/fast ion/internal transport barrier
万方数据