Simulation of neutral beam injection on EAST by NUBEAM

Abstract

Abstract:

The role of the injection angle (the angle between the axis of the neutral beam injection system and the center of the injection window) on the neutral beam current drive, heating efficiency and beam shine-through power are studied with NUBEAM code to explore the optimum injection angle for the EAST NBI system. From the simulation results, under the limitation of the actual project, it is indicated that an injection angle of 19.5° is the optimum for EAST with its typical experimental parameters. With this injection angle, the increase of the plasma density can improve the current drive and heating efficiency and reduce the beam shine-through power.

Key words: Neutral beam injection, Injection angle, Beam shine-through, Simulation

摘要：

采用蒙特卡罗程序NUBEAM对EAST NBI上的中性束注入角度(中性束系统中心线与注入窗口轴线的夹角)进行了分析。讨论了中性束注入角度对电流驱动效率、加热效率和束的穿透功率的影响，对EAST NBI系统选取了一个最优的注入角度。模拟结果表明：对EAST NBI系统，在典型的EAST实验参数和实际工程允许的范围内，19.5°是最优的注入角度。在此注入角度下，可以通过增大等离子体密度的方法来进一步提高加热效率和电流驱动效率，并减少束的穿透功率。

关键词: 中性束注入, 注入角度, 束穿透, 数值模拟

CLC Number:

WANG Jin-fang, WU Bin, HU Chun-dong. Simulation of neutral beam injection on EAST by NUBEAM[J]. NUCLEAR FUSION AND PLASMA PHYSICS, 2011, 31(2): 139-145.

王进芳，吴斌，胡纯栋. EAST中性束注入角度的NUBEAM模拟研究[J]. 核聚变与等离子体物理, 2011, 31(2): 139-145.

References

[1] Mcguire K, Goldston R, Bell M, et al. Study of high-beta magnetohydrodynamic modes and fast-ion losses in PDX[J]. Phys. Rev. Lett., 1983, 50(12): 891-895.

[2] Heidbrink W W, Bol K, Buchenauer D, et al. Tangential neutral-beam-driven instabilities in the Princeton Beta Experiment[J]. Phys. Rev. Lett., 1986, 57(7): 835-838.

[3] Strachan J D, Grek B, Heidbrink W, et al. Studies of energetic ion confinement during fishbone events in PDX[J]. Nucl. Fusion, 1985, 25(8): 863-880.

[4] Fredrickson E, Gorelenkov N, Cheng C Z, et al. Observation of compressional Alfven modes during neutral-beam heating on the National Spherical Torus Experiment[J]. Phys. Rev. Lett., 2001, 87(14): 145001.

[5] Gorelenkov N N, Berk H L, Budny R V. Beam anisotropy effect on Alfven eigenmode stability in ITER-like plasmas[J]. Nucl. Fusion, 2005, 45(4): 226-237.

[6] Chapman I T, Pinches S D, Graves J P, et al. The physics of sawtooth stabilization[J]. Plasma Physics and Controlled Fusion, 2007, 49(12): 385-394.

[7] Chapman I T, Pinches S D, Appel L C, et al. Modeling sawtooth stabilization by energetic ions from neutral beam injection[J]. Phys. Plasmas, 2007, 14(7): 070703.

[8] Chapman I T, Pinches S D, Koslowski H R, et al. Sawtooth stability in neutral beam heated plasmas in TEXTOR[J]. Nucl. Fusion, 2008, 48(3): 035004.

[9] Chapman I T, Jenkins I, Budny R V, et al. Sawtooth control using off-axis NBI[J]. Plasma Physics and Controlled Fusion, 2008, 50(4): 045006.

[10] Hamada Y, Watari T, Yamagishi O, et al. Change of zonal flow spectra in the JIPP T-IIU tokamak plasmas[J]. Phys. Rev. Lett., 2007, 99(6): 065005.

[11] Okamura S, Hanatani K, Nishimura K, et al. Heating experiments using neutral beam with variable injection angle and ICRF waves in CHS[R]. Würzburg, 1992.

[12] Taguchi M. Bootstrap current in NBI heated plasmas[J]. Nucl. Fusion, 1996, 36(5): 657-667.

[13] Na Yong Su, Sips A C C, Garbet X, et al. Modelling of the current profile control with neutral beam injection at ASDEX Upgrade and comparison to JET[R]. Russia: Petersburg, 2003.

[14] Gorelenkov N N, Cheng C Z, Fredrickson E. Compre- ssional Alfven eigenmode instability in NSTX[J]. Nucl. Fusion, 2002, 42(8): 977-985. .

[15] Wang Jinfang, Wu Bin, Hu Chundong. Simulation on heating and current drive using neutral beam injection with variable injection angle on EAST[J]. Plasma Science and Technology, 2010, 12(3): 289-294.

[16] Mandrekas J. Physics models and user’s guide for the neutral beam module of the super-code[R].United States: Atlanta, 1992.

[17] Pankin A. The tokamak Monte Carlo fast ion module NUBEAM in the national transport code collaboration library[J]. Computer Physics Communications, 2004, 159(3): 157-184.

[18] Pfeiffer W W, Davidson R H, Miller R L, et al. ONETWO: A computer code for modeling plasma transport in tokamaks[R]. San Diego: General Atomics Company, 1980.

[19] Zhou D, John H S. Transport modelling for EAST with LHRF and NBI[J]. Plasma Science and Technology, 2009, 11(4): 417-421.

[20] Rome J A, Callen J D, Clarke J F. Neutral-beam injection into a tokamak-fast ion spatial-distribution for tangential injection[J]. Nucl. Fusion, 1974, 14(2): 141-151.

[21] 石秉仁. 磁约束聚变原理与实践[M]. 北京: 原子能出版社, 1999. 207.

[22] Cordey J D. A kinetic theory of beam-induced plasma currents[J]. Nucl. Fusion, 1979, 19: 249-259.

[23] Wesson J. Tokamaks[M]. Clarendon Press, 1997. 222.

[24] NTCC module library. Http: //www.pppl.gov/NTCC[Z].