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Formation of Burgers Vortex and its Dynamics in Magnetized Plasmas

磁化等离子体中伯格斯涡的形成及其动力学

基本信息

批准号：
16540453
负责人：
KONO Mitsuo
金额：
$ 1.86万
依托单位：
Chuo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540453/
关键词：
anomalous E x B drift density hole anomalous viscosity weakly ionized plasma 異常E x Bドリフト渦励起バーガース渦粘性衝突渦の融合

项目摘要

1. A stationary solution has been obtained which shows a good agreement with the observed typhoon-like vortex in axi-symmetric system and physics behind the typhoon-like vortex has been given.2. There are two branches for the E x B drift if a centrifugal force is included. One is well known ordinary E x B drift which is determined by a balance of the Lorenz force and the potential force. Newly recognized one is an anomalous E x B drift which is realized by the Lorenz force and the centrifugal force. Since the anomalous E x B force is proportional to radial coordinate and diverges at infinity, usually this branch can be ignored. However in a typhoon like vortex, the core part of the vortex is explained by the anomalous E x B drift. Outer part of the vortex is described by an ordinary E x B drift. Thus an anomalous E x B drift is first to be identified as a physical process.3. From the force balance, the density structure is determined by the centrifugal force. The density is low at the center and increases toward the edge of the vortex. Thus the plasma has a hole at the center.4. Corresponding to the density structure the radial flow converges towards the center which is converted into an axial flow.5. The axial flow in the core part of the vortex is directed toward up-stream while the axial flow outside the vortex is directed to down-stream, which suggests the axial flow is characterized by a multiple cell structure. However this has not been fully understood.6. The potential is maximum at the center and decreases towards the edge of the vortex. The maximum of the azimuthal velocity is 1.5 times the ion sound velocity and the radial velocity is 0.5 times the ion sound velocity. Therefore the inward ion velocity is super-sonic and satisfies the Bohm condition to create a mid-air sheath. This is left unsolved.

1. 得到了一个与轴对称系统中观测到的类台风涡旋吻合较好的稳态解，并给出了类台风涡旋背后的物理现象。如果包括离心力，则E × B漂移有两个分支。一种是众所周知的普通的E × B漂移，它是由洛伦兹力和势能的平衡决定的。新发现的一种是反常的E x B漂移，它是由洛伦兹力和离心力实现的。由于反常的E × B力与径向坐标成正比，并在无穷远处发散，通常可以忽略该分支。然而，在台风型涡旋中，涡旋的核心部分可以用反常的E x B漂移来解释。涡旋的外部由一个普通的E x B漂移来描述。因此，反常的E × B漂移首先被认为是一个物理过程。从力的平衡来看，密度结构是由离心力决定的。中心密度低，向涡边缘增大。因此等离子体在中心有一个洞。与密度结构相对应的是径向流向中心收敛，向中心转化为轴向流。涡旋核心部分的轴流向上游，而涡旋外的轴流向下游，表明涡旋核心部分的轴流具有多胞体结构特征。然而，这一点还没有被完全理解。旋涡中心的势最大，向旋涡边缘的势减小。方向速度的最大值为离子声速的1.5倍，径向速度的最大值为离子声速的0.5倍。因此，向内的离子速度是超音速的，并且满足玻姆条件以形成一个空中护套。这个问题没有得到解决。