Overview of HL-2A experiment results

Abstract

Recent experiment results from the HL-2A tokamak are presented in this paper. Supersonic molecular beam injection (SMBI) with liquid nitrogen temperature propellant is used. Low temperature SMBI can form hydrogen clusters that penetrate into the plasma more deeply and efficiently. Particle diffusion coefficient and convection velocity (D = 0.5–1.5 m2 s−1 and Vconv < 40 m s−1, respectively) are obtained at the plasma periphery using modulated SMBI. Multi-probe measurements reveal the m = 0–1, n = 0 symmetries of directly measured low frequency (7–9 kHz) electric potential and field are simultaneously observed for the first time. Impurity transport is determined with the laser blow-off system and transport code. A disruption predictor has been derived based on MHD activity observations and statistical analysis. Sawtooth characteristics during ECRH are investigated and coupling between m = 1 and m/n = 2/1 modes is studied. Detachment features of HL-2A divertor are numerically and experimentally studied using the code SOLPS5.0 and measured data. The long divertor legs and thin divertor throats in HL-2A pose MHD shaping problems resulting in momentum losses even at low densities and strongly enhanced main chamber losses.

Measurements of the fast electron bremsstrahlung emission during electron cyclotron resonance heating in the HL-2A tokamak

“…It has a major radius of R = 1.65 m and a minor radius of a = 0.4 m. 15 There are 16 toroidal field coils, which can create and maintain a toroidal magnetic field ͑B T ͒ up to 2. ion temperature T i = 0.8-1.5 keV, edge safety factor q a =3-5, and a current plateau duration of 0.3-1.0 s. It has a major radius of R = 1.65 m and a minor radius of a = 0.4 m. 15 There are 16 toroidal field coils, which can create and maintain a toroidal magnetic field ͑B T ͒ up to 2. ion temperature T i = 0.8-1.5 keV, edge safety factor q a =3-5, and a current plateau duration of 0.3-1.0 s.…”

Enhanced production of runaway electrons during electron cyclotron resonance heating and in the presence of supersonic molecular beam injection in the HL-2A tokamak

“…Sixteen toroidal field coils can create and maintain a toroidal magnetic field ͑B t ͒ up to 2.8 T. The divertor of the device is characterized with two closed divertor chambers and at present it is operated with lower single null configuration. 28 The ECRH facility, consisting of four gyrotrons with the working frequency of 68 GHz, operates in the ordinary mode for delivering 2 MW power with 1 s pulse length. 29 The Gaussian beam is injected into plasma from the low field side ͑LFS͒ in fundamental O mode.…”

Progress of HL-2A physical experiments

“…最大纵向场可以达到2.8 T, 等离子体电流为 500 kA [1] . 托卡马克磁场线圈中的强电流是用三套飞 功率为2 MW, 频率为68 GHz [2] . 2006年, 在2 MW的 ECRH条件下等离子体电子温度达到了5 keV(约5500 万度) [2] , 创下了我国磁约束核聚变实验装置最高等离…”