Design and simulation of the transverse magnetic scanning system of gyrotron oscillator collector
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摘要: 从降低收集极表面峰值功率和平均功率入手,设计了一种由12个横向椭圆交流线圈和2个轴向直流线圈组成的磁场扫描系统。针对140 GHz、TE28,8模、1 MW功率输出回旋振荡管收集极的设计参数,结合电磁场理论和带电粒子电磁软件仿真,获得收集极表面上电子注的峰值和平均功率密度分别不超过404.91 W/cm2和244.01 W/cm2,以及扫描长度达到443.33 mm的扫描效果,有效地缓解了收集极功率耗散和冷却的压力。Abstract: Starting from reducing the peak power and average power on the collector surface of a gyrotron oscillator, we have designed a magnetic field scanning system composed of 12 transverse elliptical AC coils and 2 longitudinal DC coils. According to the design parameters of the collector electrode of 140 GHz, TE28, 8 mode, 1 MW gyrotron oscillator, and combining electromagnetic field theory with particle-in-cell (PIC) simulation program, the scanning system can realize that the peak and average power density of the electron beam on the collector surface are not more than 404.91 W/cm2 and 244.01 W/cm2 respectively with a scanning length of 443.33 mm, which effectively alleviates the pressure of power dissipation and cooling of the collector.
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Key words:
- gyrotron oscillator /
- collector /
- transverse magnetic field scanning /
- elliptical coil /
- power density
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表 1 回旋管部分参数
Table 1. Parameters of gyrotron
anode voltage U0 /kV modulated anode voltage Um/kV current I0 /A electron injection efficiency ηe/% 81 54 40 35 表 2 不同情况下收集极上电子注的分布参数
Table 2. Electron beam parameters on the collector surface under different conditions
coils loaded on the collector peak power density/ (W/cm2) mean power density/ (W/cm2) vertical scan length/ mm non-coil 3523.40 1820.92 58.74 1VF_coil 2803.23 1363.46 78.45 6TF_coils 679.51 318.23 336.10 6TF_coils &1VF_coil 574.81 271.86 393.43 表 3 电子注分布参数对比
Table 3. Comparison of electronic beam distribution parameters
coils loaded on the collector peak power density/(W/cm2) mean power density/(W/cm2) vertical scan length/mm 6TF_coils &1VF_coil 574.81 271.86 393.43 12TF_coil &1VF_coil 688.24 353.49 303.33 表 4 轴向扫描线圈个数不同时收集极上电子注的分布参数
Table 4. The electron beam distribution parameters on the collector surface for different number of VF_coils
coils loaded on the collector peak power density/(W/cm2) mean power density/(W/cm2) vertical scan length/mm 12TF_coil &1VF_coil 688.24 353.49 303.33 12TF_coils &2VF_coils 472.99 272.29 396.67 12TF_coils &3VF_coils 633.75 327.55 326.67 12TF_coils &4VF_coils 547.14 288.69 373.33 表 5 图8(b)中三种情况对应的收集极上轴向功率密度的分布参数
Table 5. The distribution parameters of the axial power density on the collector corresponding to the three cases in Figure 8(b)
(Zmin_TFSS,Zmax_TFSS) peak power density/(W/cm2) mean power density/(W/cm2) vertical scan length/mm (710,1545) 426.52 251.17 431.67 (720,1555) 404.91 244.01 443.33 (730,1565) 477.18 238.26 455.00 表 6 与现有方案的参数对比
Table 6. Comparison of parameters with existing schemes
frequency/
GHzdissipated
power /MWpeak power
density/(W/cm2)vertical scan
length/mmampere turns
of TF_coils/(kA·T)ampere turns
of VF_coils/(kA·T)number of
coils(TF,VF)ref.[12] W-band 0.5-1 130 480 mm 1.554(6A×259T) 0.81(5A×162T) (6,1) ref.[13] 140 0.1 450 − 7 0 (6,1) ref.[14] 140 1 − 330 mm 7.9 1 (6,1) ref.[15] 140 1 370 380 mm − − (6,1) ref.[16] 170 1 288.66 − 4 10 (6,1) this paper 140 1.2 404.91 443.33 2.4 1.56 (12,2) 表 7 TFSS仿真模型关键参数
Table 7. Key parameters of TFSS simulation model
type of
coilsouter
radius(mm)thickness/mm length/mm ampere turns of
single coil /(kA·turn)number of
coilsdistance from coils’
center to origin/mmTF_coils 160(SMA)
70(SMI)30 50 2.4(6A×400T) 12 880 VF_coils 220 10 240 1.56(5.2A×300T) 2 1320 -
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