Study on collision between a current loop and a plasma cloud in solar flares

太阳耀斑中电流环与等离子体云碰撞的研究

• 批准号: 07640352
• 负责人: SAKAI Jun-ichi
• 金额: $ 1.47万
• 依托单位: Toyama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640352/
• 关键词: solar flare; Current loop; Particle Acceleration; Current loop; Particle Acceleration; Cerrent loop; Particle acceleration; particle accelaration

One of important unsolved problems in Plasma Astrophysics is how the magnetic field energy released during a solar flare can be converted to plasma heating as well as high energy particle acceleration.A new flare observed by the YOHKOH sattelite, which is so called as Masuda-flare showed a loop structure in the soft X-ray image with hard X-ray source, which location is just above the soft X-ray loop top. To explain this flare, Masuda et al.proposed a model that this flare was caused by the interaction between a current loop and a plasmoi(plasma cloud).(1) In order to explain the X-ray source observed in this flare, we investigated the collision process between a current loop and a plasma cloud by using 3-D MHD code and 3-D particle code, and made clear the plasma heating process and the mechanism of high energy electron acceleration.(2) We investigated the coalescence process of X-type current loop collision by 3-D MHD simulation and compared with a typical X-type flare on the 1993, Aug.2. The result showed a good agreement on the temperature variation between the observation and the simulation.(3) The recombination effect becomes important for the reconnection process in the chromosphere. This effect was investigated by the MHD simulation with recombination effect. It has been shown that the recombination effect greatly enhances the plasma heating during the magnetic reconnection in the chromosphere.(4) The nonlinear behavior of Alfven waves in weakly ionized plasmas was investigated and it was shown that the modulational instability of the Alfven waves is important for the local plasma heating. The results were applied to the solar chromospheric heating.

太阳耀斑释放的磁场能量如何转化为等离子体加热和高能粒子加速是等离子体天体物理学中尚未解决的重要问题之一。为了解释这一耀斑，增田等人提出了一个模型，认为这一耀斑是由电流环和等离子体云（plasmoi）之间的相互作用引起的。(1)为了解释在这次耀斑中观测到的X射线源，我们利用三维MHD程序和三维粒子程序研究了电流环与等离子体云的碰撞过程，阐明了等离子体加热过程和高能电子加速机制。(2)本文用三维MHD模拟研究了X型电流环碰撞的并合过程，并与1993年8月2日发生的一次典型X型耀斑进行了比较。结果表明，模拟结果与实测结果吻合较好。(3)复合效应对于色球层中的重联过程变得重要。通过考虑复合效应的MHD模拟研究了这种效应。结果表明，在色球磁场重联过程中，复合效应大大增强了等离子体的加热。(4)研究了弱电离等离子体中Alfven波的非线性行为，指出Alfven波的调制不稳定性对等离子体局部加热是重要的。结果被应用到太阳色球加热。

项目成果

Sakai,J.: "3-D MHD Simulation of X-type Coalascence of Two Current Loops" Solar Physics. (印刷中). (1997)

Sakai, J.：“两个电流环路的 X 型聚结的 3-D MHD 模拟”太阳物理学（正在出版）。

Zaqarashvili, T.: "The Role of Loop Footpoints Rotation in Single Loop Flares" Astrophysics and Space Science. 246. 107-118 (1997)

Zaqarashvili, T.：“环足点旋转在单环耀斑中的作用”天体物理学和空间科学。

Zaqarashvili, T.: "The Role of Loop-Footpoints Rotation in Single Loop Flares" Astrophysics and Space Science. 246. 107-118 (1997)

Zaqarashvili, T.：“环足点旋转在单环耀斑中的作用”天体物理学和空间科学。

Sakai,J.: "3-D MHD Simulation of X-type Coalescence of Two Current Loops" Solar Physics. 173. 347-358 (1997)

Sakai,J.：“两个电流环路 X 型合并的 3-D MHD 模拟”太阳物理学。

Suzuki, M.: "Filamentation Instability of Nonlinear Alfoen Waves in Weakly Ionged Plasmas" The Astrophysical Journal. 487. 921-929 (1997)

Suzuki, M.：“弱离子等离子体中非线性阿尔芬波的细丝不稳定性”《天体物理学杂志》。