Large-Amplitude Magnetosonic Waves in Muiti-Ion-Species Plasmas

多离子等离子体中的大振幅磁声波

基本信息

批准号：
09680460
负责人：
OHSAWA Yukiharu
金额：
$ 1.98万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680460/
关键词：
multi-ion-species plasma magnetosonic wave particle acceleration wave demping energetic particles strong magnetic field shock wave nonlinearity

项目摘要

We have studied, by theory and simulations, propagation of large-amplitude magnetosonic waves and associated particle acceleration in plasmas containing multiple ion species.By using a relativistic particle simulation code, we found that a magnetosonic shock wave can accelerate all the heavy ions to nearly the same speed. This mechanism is different from that of hydrogen acceleration. Thus, as in the solar energetic particles, the high-energy heavy ions have the elemental composition same as that of the background plasma.Magnetosonic pulses are found to be damped in a two-ion-species plasma even if their amplitudes are small and their propagation angles are perpendicular to a magnetic field. This occurs in both the low- and high-frequency modes. This could be an important energy dissipation mechanism in collisionless plasmas such as solar corona.We studied interactions of nonthermal energetic ions with magnetosonic shock waves. Simulations show that some energetic ions can be further accelerated by a shock wave. This result suggests that some ions can be accelerated many times by many different. magnetosonic pulses ; they could therefore obtain quite high energies.We found that ultra-relativistic electrons can be produced in a large-amplitude oblique shock wave. Lorentz factors with gamma > 100 have been observed in our simulations.Large-amplitude magnetosonic waves with relativistic propagation speeds were studied. We theoretically obtained magnetic and electric field strengths as a function of the propagation speed and then analyzed ion motions in such shock waves.

通过理论和模拟，我们研究了包含多个离子物种的血浆中大振幅磁波和相关颗粒加速度的传播。通过使用相对论粒子模拟代码，我们发现磁性冲击波可以将所有重离子加速至几乎相同的速度。该机制与氢加速度不同。因此，与太阳能颗粒一样，高能量重离子具有与背景等离子体相同的元素组成。MAGNETOSONIONSONIC脉冲被发现在两离子物种的血浆中受阻，即使它们的振幅较小，并且它们的传播角度均透露于磁场。这是在低频和高频模式中发生的。这可能是无碰撞等离子体（例如太阳电晕）的重要能量耗散机制。我们研究了非热能离子与磁性冲击波的相互作用。模拟表明，冲击波可以进一步加速某些能量的离子。该结果表明，某些离子可以被许多不同的次数加速。磁性脉冲；因此，他们可以获得很高的能量。我们发现，可以在大振幅倾斜的冲击波中产生超相关的电子。在我们的模拟中已经观察到了具有γ> 100的洛伦兹因子。研究了具有相对论传播速度的Large-振幅磁波。我们从理论上获得了磁性和电场强度作为传播速度的函数，然后在这种冲击波中分析了离子运动。