Particle Acceleration and Plasma Heating due to Cyclotron Subharmonic Wave

回旋子谐波引起的粒子加速和等离子体加热

• 批准号: 60580009
• 负责人: ABE Hirotada
• 金额: $ 0.45万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60580009/
• 关键词: Subharmonic Frequency; Simulation; Plasma Heating; エネルギー緩和

The purpose of this project is that the property on the resonant heating due to cyclotron subharmonic wave of frequency = (n/2) _i discovered by us is examined in detail.In 1985 fiscal year, we have carried out the simulation on 5/2 _i resonant heating, succeeding the simulation on 3/2 _i resonant heating, originally studied. This work has been requested by the experimentalists. Any qualitative differences are not found out between the 5/2 and 3/2 resonant heating, and therefore, these two heating mechanisms are the same in essence.Since 1986, Porkolab at MTT has attempted to explain this heating mechanism from the different aspect from ours. The mechanism proposed by him is named the nonlinear Landau damping and is characterized by appearance of the virtual wave. Therefore, it is controversial in the world and thus we have needed to reexamine our claim on the heating mechanism.First, we have confirmed that its heating rate in time has shown a feature of the nonlinear process. Second w … More e have an analytical solution of the averaged particle orbit by adopting the method of the multi-time scaling. Third we have observed the existence of the virtual wave. However, its amplitude is about 10 % in the wave energy compared with the pump wave and is so small that the virtual wave affects the heating by only about 10 %. Therefore, the rest part of the heating should be by interpreted in terms of the cyclotron subharmonic heating.Our original claim is that the wave of frequency = (n/2) _i forms islands resonantly in phase space of the ion particle orbit and ion is accelerated efficiently due to a particle trapping in this island and that the resonant feature of the energy deposition around = (n/2) _i layer is the result of the ion acceleration efficiency enhancement due to this trapping.If this heating mechanism results from the phenomenon of the single particle trapping, however, heating should be saturated in an early time. If some energy relaxation mechanism exists, on the other hand, this mechanism can be considered as a true heating mechanism.In order to see whether the energy relaxation mechanism exits in plasma or not, we have carried out the simulations in the simple system where the magnetic field and the plasma density are uniform. We have tested two cases: One is the weak and the other is the large amplitude case. In either case, the saturation of the heating is not observed. This means that the simple system of plasma itself involves some enegy relaxation relaxation mechanism. Finally we have shown that the very small binary collision in plasma owes to this energy relaxation mechanism. Less

本项目的目的是详细研究我们发现的频率为(n/2)_i的回旋亚谐振波的共振加热特性。在1985财政年度，我们在原有研究的3/2_i共振加热的基础上，进行了5/2_i共振加热的模拟。这项工作是应实验者的要求进行的。5/2和3/2共振加热之间没有发现任何定性的区别，因此，这两种加热机制在本质上是相同的。自1986年以来，波科拉布在MTT试图从与我们不同的角度来解释这种加热机制。他提出的机制称为非线性朗道阻尼，其特征是虚波的出现。因此，这在世界上是有争议的，因此我们需要重新审视我们对加热机制的主张。首先，我们确认了它的升温速度在时间上表现出了非线性过程的特征。第二个w…采用多时间标度法给出了平均粒子轨道的解析解。第三，我们观察到了虚波的存在。但由于虚波的波幅约为抽运波能量的10%，虚波对加热的影响仅为10%左右。因此，加热的其余部分应该用回旋亚谐加热来解释。我们最初的主张是，频率=(n/2)_i的波在离子粒子轨道的相空间共振形成孤岛，由于离子在岛上的粒子陷阱，离子被有效地加速，而=(n/2)_i层周围能量沉积的共振特征是由于这种陷阱导致离子加速效率提高的结果。如果这种加热机制是由单个粒子陷阱现象引起的，那么加热应该在早期达到饱和。为了考察等离子体中是否存在能量弛豫机制，我们在磁场和等离子体密度均匀的简单系统中进行了模拟计算。我们测试了两种情况：一种是弱的情况，另一种是大幅度的情况。在任何一种情况下，都没有观察到加热的饱和。这意味着简单的等离子体系统本身就包含了一些能量弛豫机制。最后，我们证明了等离子体中非常小的二元碰撞归功于这种能量弛豫机制。较少

项目成果

岡田英俊,阿部宏尹,板谷良平,小野雅之: The Physics of Fluids. 29. 489-500 (1986)

Hidetoshi Okada、Hirotaka Abe、Ryohei Itaya、Masayuki Ono：流体物理学。29. 489-500 (1986)

H. Okada.; H. Abe,;R. Itatani; M. Ono: "Computational Study on Propagation and Two-Species-Ion-Plasma Heating due to the Ion-Bernstein Wave" Plasma Physics and Contrlled Fusion. 29. 743-757 (1987)

H.冈田。

阿部宏尹,岡田英俊,板谷良平,小野雅之,奥田英雄: Physical Review Letters. 53. 1153-1156 (1984)

Hirotaka Abe、Hidetoshi Okada、Ryohei Itaya、Masayuki Ono、Hideo Okuda：物理评论快报 53。1153-1156 (1984)。

H. Abe,;H. OKada,;R. Itatani,; M. Ono; H. Okuda: "Resonant Heating due to Cyclotron Subharmonic Frequency Waves" Physical Review Letters. 53. 1153-1156 (1984)

H.阿部，;H.

H. Okada.;H. Abe.;R. Itatani.; M. Ono: "Computational Study on Excitation, Propagation, and Two-Species-Plasma Heating due to the Ion-Bernstein Wave" The Physics of Fluids. 29. 489-500 (1986)

H.冈田；H.