摘要：
The effect of local toroidal flow (LTF) on double-tearing modes (DTMs) is investigated in cylindrical geometry using the reduced magnetohydrodynamics (RMHD) model. The results indicate that the LTF between the two rational surfaces is the dominant suppression effect on DTMs. The suppression effect is enhanced with the flow width increasing, and the DTMs become more stable with the increase of the shear of the LTF between the two rational surfaces. So, in the reversed shear magnetic field configuration, the local flow is driven between the two rational surfaces, which can effectively suppress the development of DTMs and maintain the high-performance state.
作者机构：
[Gong, Xueyu; He, Liang; Yang, Jin; Lu, Xingqiang; Wang, Xunyu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Bin, Bin; Li, Yingying; Wan, Shunkuan; Chen, Jun; Fu, Jia; Wang, Fudi; Hao, Baolong; He, Liang; Wan, Baonian; Lyu, Bo; Zhang, Hongming; Yang, Jin; Li, Yichao; Wang, Xunyu] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.;[Solomon, W. M.] Gen Atom, San Diego, CA 92186 USA.;[Chen, Jun; Ye, Minyou] Univ Sci & Technol China, Dept Engn & Appl Phys, Hefei 230026, Peoples R China.
通讯机构：
[Lu, Xingqiang] U;[Lyu, Bo] C;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.
关键词：
intrinsic torque;balanced injection;momentum transport
摘要：
Direct measurements of the intrinsic torque profile in L-mode plasmas on the EAST tokamak have been performed using the balanced neutral beam injection. Co- and counter-current neutral beams are modulated to balance the intrinsic and externally injected torques, which result in the rotation profile close to zero and flat. The experimental results show that the intrinsic torque derived from momentum balance equations is found to be in the co-current direction, peaked in the plasma edge and negligibly small in the core.
作者机构：
[袁赟; 路兴强; 龚学余; 尹陈艳; 陈诗佳] School of Nuclear Science and Technology, University of South China, Hengyang;421001, China;[袁赟; 路兴强; 龚学余; 尹陈艳; 陈诗佳] 421001, China
通讯机构：
School of Nuclear Science and Technology, University of South China, Hengyang, China
作者机构：
[Xingqiang Lu; Yuan Yun; Xueyu Gong] School of Nuclear Science and Technology,University of South China
会议名称：
The 2nd International Conference on Matter and Radiation at Extremes(ICMRE 2017)
会议时间：
2017-06-26
会议地点：
中国北京
摘要：
The effect of helical driven current on the m=2/n=l tearing mode are studied numerically in cylindrical geometry using the method of reduced magneto-hydro-dynamic(RMHD) simulation.The results show tha
摘要：
Fast wave in the ion-cyclotron resonance frequency (ICRF) range is a promising candidate for non-inductive current drive (CD), which is essential for long pulse and high performance operation of tokamaks. A numerical study on the ICRF fast wave current drive (FWCD) and mode-conversion current drive (MCCD) in the Experimental Advanced Superconducting Tokamak (EAST) is carried out by means of the coupled full wave and Ehst-Karney parameterization methods. The results show that FWCD efficiency is notable in two frequency regimes, i.e., integral >= 85 MHz and integral = 50-65 MHz, where ion cyclotron absorption is effectively avoided, and the maximum on-axis driven current per unit power can reach 120 kA/MW. The sensitivity of the CD efficiency to the minority ion concentration is confirmed, owing to fast wave mode conversion, and the peak MCCD efficiency is reached for 22% minority-ion concentration. The effects of the wave-launch position and the toroidal wavenumber on the efficiency of current drive are also investigated. Published by AIP Publishing.
作者机构：
[李新霞; 路兴强; 陈诗佳; 龚学余] School of Nuclear Science and Technology, University of South China, Hengyang, 421001, China;[何志雄] Southwestern Institute of Physics, Chengdu, 610041, China
通讯机构：
School of Nuclear Science and Technology, University of South China, Hengyang, China
摘要：
The delay time dependence of photoelectron spectra and state populations of three-level ladder K2 molecule is investigated by pump-probe pulses via time-dependent wave packet approach. The periodical motion of the wave packet with oscillating period 500 fs results in the periodical variation of photoelectron spectra. The photoelectron spectra show Autler-Townes double splitting at zero delay time, and no splitting at positive delay time. The periodical change of state populations with delay time can be ascribed to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide some important basis for realizing the optical control of molecules experimentally.
作者机构：
[Lu, Xingqiang] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Ma, Zhiwei] Zhejiang Univ, Inst Fus Theory & Simulat, Hangzhou 310027, Zhejiang, Peoples R China.;[Guo, Wei] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Ma, Zhiwei] Z;Zhejiang Univ, Inst Fus Theory & Simulat, Hangzhou 310027, Zhejiang, Peoples R China.
摘要：
Behavior of the fast earthward flow near the braking region in the magnetotail during a substorm is investigated using the Hall MHD simulation. The results indicate that the high-speed earthward plasma flow is associated with fast reconnection in the middle tail. The fast flow is mainly confined in the range -1.5R(E) < z < 1.5R(E). In the region of -15R(E) < x < -9R(E), due to intermittent magnetic reconnection, the earthward flow exhibits a fluctuating property, i. e., the flow is localized in space and is bursty in time. The pile-up of the magnetic flux and plasma in the near-Earth region leads to formation of the fast-flow braking region or dipolarization front. After colliding into the fast-flow braking region, a part of the Earth flow bounces back, and leads to an intermittent tailward flow in the near-Earth magnetotail.
摘要：
The effect of toroidal plasma rotation on q = 3 double tearing modes (DTMs) was studied numerically in cylindrical geometry using the method of reduced magnetohydrodynamic simulation. The results indicate that toroidal plasma rotation can reduce the growth rate of DTMs, but the magnitude of toroidal velocity has weak effect, especially without shear. When the shear of toroidal velocity exists, the suppression effect becomes better. Whether the velocity flow has shear or not, the growth rate of DTMs decreases as the magnitude of toroidal velocity increases. With the increase of velocity shear, the DTMs grow slowly. And the suppression effect of toroidal plasma rotation in early growth and transition stage is better, which means that the toroidal plasma rotation can suppress the linear growth of islands. Furthermore, the toroidal plasma rotation can suppress the evolution of poloidal stream. And the toroidal velocity shear on the q = 3 rational surface is more dominant than the magnitude of toroidal velocity in determining the DTM characteristics. Published by AIP Publishing.
