The NBI (Neutral Beam Inject) system of EAST has two deuterium beam lines, in which beam power is 4 MW and energy is 80 keV. To study the neutral beam shinethrough power loss, the physics processes of neutral beam attenuation in plasma are described and simulated by the code ONETWO/NUBEAM. The simulated input plasma parameter forms are tested through curve fitting of measured shinethrough in DIII-D. The power density distribution of shinethrough is obtained by analytical governing expression. The surface temperature rise testing for a copper target is also discussed.
Sup erconducting Tokamak* HU Jian-sheng (&I @ &) , LI Jian-gang ($ @ wu), ZHANG Shou-yin (% *&), GU Xue-mao ($%B), ZHANG Xiao-dong (?&%%), ZHAO Yan-pin (&ay), GONG Xian-zu (g%%), KUANG G u a n g -l i ( E % a ) , LI Cheng-fu (+&%), LUO Jia-rong (y@@), WANG Xiao-rning (E/]\ m),GAO Xiang (am),
In the analysis of HT-7 superconductive tokamak which consists of iron core, thick copper shell and multi-coupling coils system, the electromagnetic parameters are linearized by a novel method; the copper shell is replaced by an equivalent pair of coils in series-opposing; and the multi-coupling is compensated by an intermediate state variable. As a result, the plasma control equation can be set up and solved more simply and easily. The feed-back control system has been designed and rather good results were obtained in experiment. This feed-back control system has high response speed, less computing time and is easy to carry out.
The three well-known parameters of motion (magnetic momentum, energy and canonical toroidal momentum) are utilized to develop a guiding center orbit code, GCORBIT. The effect of poroidal field ripple and toroidal angle scatter is considered in the GCORBIT. It is applied to compute guiding center orbit of charged particle in axisymmetric tokamak, the loss region of velocity space and the loss fraction of fast ions.To compare achieved results, the loss region of velocity space by GCORBIT includes many effects: non-closed orbit of divertor, first orbit loss by guiding-center orbit being non-closed or intersecting with any material limiters, trapping by the poroidal field ripple in local magnetic wells, ripple random diffusion and toroidal angle scatter enabled by velocity space discontinuous confinement region. The GCORBIT is now being used to analyze the confinement of fast ions in EAST Tokamak. Our numerical calculations are focused on the loss of fast ions.
Using a small pulse of toroidal vortex eletric field (4.4V/m, 0.45ms), plasma current is successfully ramped up from the plateau (55kA) to the second plateau (60kA) with a ramp rate dIp/dt>12MA/s on a time scale much fast than the classical skin time in the HT-6M Tokamak. The phenomena of improved confinement is observed in the present experiment. Particle confinement time is enhanced 2.1 times and energy confinement time, meanwhile, is enhanced 1.6 tines after ramping current up.
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