Three dimensional electromagnetic analysis of the four strap ICRF antenna for EAST

doi:10.16568/j.0254-6086.201503008

Abstract

Abstract:

The performance of the four strap ion cyclotron range of frequency (ICRF) antenna in EAST was studied by three dimensional electromagnetic code CST MWS. The coupling impedance with various frequencies, the distribution of current on straps and the power spectra for the three types of phases were calculated. The voltage breakdown and ICRF-related impurity were also studied. Simulation results show that the coupling impedance and power spectrum of the antenna design were reasonable, however, highest electric field, which is 3.61MV•m⁻¹ for (0, 0, 0, 0) toroidal phasing at the local area, exceeds the empirical value of breakdown. After the structure size was optimized, the maximum of E-field was below the breakdown value, the results also show that the high radio frequency (RF) potential was close to the antenna limiter, the RF potential along total B-field in front of Faraday screens 10mm for (0, π, π, 0) phasing was one-third of that for (0, 0, π, π) phasing.

Key words: ICRF antenna, Electromagnetic field, EAST, CST MWS code

摘要：

采用3 维电磁场代码CST MWS 对EAST 4 条带的离子回旋(ICRF)天线性能进行模拟研究，分析了天线的耦合阻抗随频率的变化，计算了电流和波谱的分布，模拟研究了不同电流相位对天线的电压击穿打火和引入杂质的影响。计算结果表明：此EAST 的ICRF 天线耦合阻抗和波谱总体设计合理；但天线局部电场较高，当环向电流条带为(0, 0, 0, 0)相位时E_max 为3.61MV•m⁻¹超出击穿阈值，经过结构尺寸的优化后E_max低于阈值。同时表明天线运行时限制器处有较高的RF 电势，当电流相位为(0, π, π, 0)时法拉第屏前10mm 处的RF 电势是(0, 0, π, π)相位时的1/3。

关键词: 离子回旋天线, 电磁场, EAST, CST MWS 代码

CLC Number:

TL62+4

YANG Hua1, WU Cong-feng1, DONG Sai1, ZHANG Xin-jun2,ZHAO Yan-ping2, SHANG Lei1. Three dimensional electromagnetic analysis of the four strap ICRF antenna for EAST[J]. NUCLEAR FUSION AND PLASMA PHYSICS, 2015, 35(3): 233-239.

杨桦1，吴丛凤1，董赛1，张新军2，赵燕平2，尚雷1. EAST 四条带ICRF 天线的三维电磁场分析[J]. 核聚变与等离子体物理, 2015, 35(3): 233-239.

References

[1] Zhao Y P. ICRF heating system[R]. Hefei: Institute of Plasma Physics Chinese Academy of Sciences, 2006.
[2] Yang X Q, Song Y T, Wu S T, et al. Mechanical design of the second ICRF antenna for EAST[J]. Fusion Engineering and Design, 2012, 87(7): 1249−1252.
[3] Ryan P M, Carter M D, Goulding R H, et al. Integrated design and analysis of RF heating and current drive systems[R]. The 11th Topical Conference on Radio Frequency Power in Plasmas, AIP Publishing, 2008,355(1): 355−363.
[4] Kaye A, Brown T, Bhatnagar V, et al. Present and future JET ICRF antenna [J]. Fusion Engineering and Design,1994, 24(1): 1−21.
[5] Kaye A S, Bhatnagar V, Bures M, et al. ICRF system in the JET pumped divertor configuration[C]. Proceedings of 16th International Symposium on Fusion Engineering.IEEE, 1995, 1: 736−741.
[6] Schilling G, Wukitch S J, Boivin R L, et al. Analysis of 4-strap ICRF antenna performance in Alcator C-Mod[C].Radio Frequency Power in Plasmas: 15th Topical Conference on Radio Frequency Power in Plasmas. AIP Publishing, 2003, 694(1): 166−169.
[7] Messiaen A, Koch R, Weynants R R, et al. Performance of the ITER ICRH system as expected from TOPICA and ANTITER II modelling[J]. Nucl. Fusion, 2010,50(2): 025026−025046.
[8] Zammuto I, Krivska A, Bobkov V, et al. ICRF antennas optimized for operation with a high-Z metallic wall in ASDEX Upgrade[J]. Fusion Engineering and Design,2009, 84(7): 2031−2036.
[9] Kyrytsya V, Dumortier P, Louche F, et al. Parametric study of one triplet of the ITER ICRH antenna by numerical modeling[J]. Fusion Engineering and Design,2011, 86(6): 901−904.
[10] Louche F, Dumortier P, Messiaen A, et al. 3D electromagnetic optimization of the front face of the ITER ICRF antenna[J]. Nucl. Fusion, 2011, 51(10):103002−103021.
[11] Lamalle P U, Messiaen A M, Dumortier P, et al. Recent developments in ICRF antenna modelling[J]. Nucl.fusion, 2006, 46(4): 432−443.
[12] Wukitch S J, Boivin R L, Bonoli P T, et al. Investigation of performance limiting phenomena in a variable phase ICRF antenna in Alcator C-Mod[J]. Plasma Physics and Controlled Fusion, 2004, 46(9): 1479−1491.
[13] Koert P, Lin Y, Mucic N P, et al. New Alcator C-Mod rotated 10 degrees 4-strap ICRF antenna[C]. 23rd IEEE/NPSS Symposium on Fusion Engineering, IEEE,2009: 482−484.
[14] Bobkov V V, Braun F, Dux R, et al. Assessment of compatibility of ICRF antenna operation with full W wall in ASDEX Upgrade[J]. Nucl. Fusion, 2010, 50(3):035004−035014.
[15] Maggiora R, Vecchi G, Carter M D, et al.Electromagnetic design of an ICRH system for IGNITOR[J]. Fusion engineering and design, 1998,38(4): 353−367.
[16] 朱学光, 匡光力, 赵燕平, 等. 快波加热的天线设计[J]. 计算物理, 2000, 17(6): 712−718.
[17] Zhang X J, Zhao Y P, Wan B N, et al. Physics and engineering aspects of the icrf heating system on EAST[R]. 23nd IAEA Fusion Energy Conference, Daejon,South Korea, 2010.
[18] Myra J R, D'Ippolito D A, Russell D A, et al. Nonlinear ICRF-plasma interactions[J]. Nucl. Fusion, 2006, 46(7):S455−S468.
[19] Jacquet P, Colas L, Mayoral M L, et al. Heat loads on JET plasma facing components from ICRF and LH wave absorption in the SOL[J]. Nucl. Fusion, 2011, 51(10): 103018−103033.