Microwave emission related to cyclotron instabilities in a minimum-B electron cyclotron resonance ion source plasma
Microwave emission related to cyclotron instabilities in a minimum-B electron cyclotron resonance ion source plasma
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DOI：
10.1088/0963-0252/24/4/045017
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发表时间：
2015-07
影响因子：
3.8
通讯作者：
I. Izotov;O. Tarvainen;D. Mansfeld;V. Skalyga;H. Koivisto;T. Kalvas;J. Komppula;R. Kronholm;J. Laulainen
中科院分区：
文献类型：
--
作者：
I. Izotov;O. Tarvainen;D. Mansfeld;V. Skalyga;H. Koivisto;T. Kalvas;J. Komppula;R. Kronholm;J. Laulainen
电子回旋共振离子源（ECRIS）在过去的40年里一直是核物理研究和应用中必不可少的。它们广泛用于各种大型加速器设施，用于产生稳定和放射性元素的高电荷重离子束。由于共振加热机制导致各向异性的电子速度分布函数，ECRI对动力学不稳定性敏感。回旋加速器类型的不稳定性是经常观察到的“热”电子和韧致辐射的周期性爆发的一个被证明的原因，伴随着微波辐射的发射，随后是多电荷离子电流的显著下降。与不稳定性的微波辐射的详细研究已经进行了最小B 14 GHz ECRIS操作氦，氧和氩等离子体。它表明，在回旋不稳定性的发展过程中，“热”电子发射微波在亚微秒尺度的突发在时间上下降的频率在8-15 GHz的范围内，两个主频率为11.09和12.59 GHz的ECRIS设置，即磁场强度，中性气体压力或物种和微波功率。实验数据表明，最可能的激发等离子体波是一个缓慢的非常Z模式传播准纵向相对于外部磁场。
Electron cyclotron resonance ion sources (ECRIS) have been essential in the research and applications of nuclear physics over the past 40 years. They are extensively used in a wide range of large-scale accelerator facilities for the production of highly charged heavy ion beams of stable and radioactive elements. ECRISs are susceptible to kinetic instabilities due to resonance heating mechanism leading to anisotropic electron velocity distribution function. Instabilities of cyclotron type are a proven cause of frequently observed periodic bursts of ‘hot’ electrons and bremsstrahlung, accompanied with emission of microwave radiation and followed by considerable drop of multiply charged ions current. Detailed studies of the microwave radiation associated with the instabilities have been performed with a minimum-B 14 GHz ECRIS operating on helium, oxygen and argon plasmas. It is demonstrated that during the development of cyclotron instability ‘hot’ electrons emit microwaves in sub-microsecond scale bursts at temporally descending frequencies in the 8–15 GHz range with two dominant frequencies of 11.09 and 12.59 GHz regardless of ECRIS settings i.e. magnetic field strength, neutral gas pressure or species and microwave power. The experimental data suggest that the most probable excited plasma wave is a slow extraordinary Z-mode propagating quasi-longitudinally with respect to the external magnetic field.