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arXiv 1104.1679physics.plasm-phphysics.acc-ph
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磁化电子等离子体中离子的冷却力

Cooling force on ions in a magnetized electron plasma

H. B. Nersisyan, G. Zwicknagel

摘要:

电子冷却是改善储存环中离子束相空间质量的有效方法。在离子和电子束的共同静止坐标系中,离子受到拖曳力,并且其经历能量的损失或增益,这最终减小了离子束的能量扩散。由于电子速度分布是各向异性的,并且冷却过程发生在引导电子的磁场中,因此该过程的计算是复杂的。在本文中的冷却力计算的离子和磁化的电子之间的二进制碰撞(BC)的模型中,库仑相互作用被处理到二阶作为扰动的螺旋运动的电子。该理论对任何强度的磁场都是一致有效的,并且在傅立叶空间中的相互作用中处理了二阶两体力,而没有指定相互作用势。冷却力的显式计算的正则化和屏蔽的潜力,这是有限的范围和更少的奇异性比库仑相互作用在原点。本文导出了单色电子束的封闭表达式,它与电子和离子的速度分布折叠。所得到的冷却力的各向异性麦克斯韦速度分布的电子和离子进行评估。

英文摘要:

Electron cooling is a well-established method to improve the phase space quality of ion beams in storage rings. In the common rest frame of the ion and the electron beam the ion is subjected to a drag force and it experiences a loss or a gain of energy which eventually reduces the energy spread of the ion beam. A calculation of this process is complicated as the electron velocity distribution is anisotropic and the cooling process takes place in a magnetic field which guides the electrons. In this paper the cooling force is calculated in a model of binary collisions (BC) between ions and magnetized electrons, in which the Coulomb interaction is treated up to second-order as a perturbation to the helical motion of the electrons. The calculations are done with the help of an improved BC theory which is uniformly valid for any strength of the magnetic field and where the second-order two-body forces are treated in the interaction in Fourier space without specifying the interaction potential. The cooling force is explicitly calculated for a regularized and screened potential which is both of finite range and less singular than the Coulomb interaction at the origin. Closed expressions are derived for monochromatic electron beams, which are folded with the velocity distributions of the electrons and ions. The resulting cooling force is evaluated for anisotropic Maxwell velocity distributions of the electrons and ions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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