Scattering of magnetized electrons by ions
Scattering of magnetized electrons by ions
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DOI：
10.1103/physreva.66.022714
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发表时间：
2002-08
影响因子：
2.9
通讯作者：
C. Toepffer
中科院分区：
文献类型：
--
作者：
C. Toepffer
在二阶微扰理论中，从电子的未扰动螺旋运动出发，讨论了离子和电子在外磁场中的二元碰撞。对于在碰撞中的相对速度的转移，三个运动学制度被确定，这取决于回旋半径的相对大小，螺旋的节距，和最近的方法的距离。只要离子速度本身具有横向分量，磁场就会抑制横向方向的速度传递，但会增强纵向速度传递。为了将速度转移与离子的能量损失联系起来，必须特别注意磁场中质心运动的不守恒。硬碰撞是通过正则化小距离处的能量转移来解释的。对于离子与单色光束相互作用的能量损失的封闭表达式可以推导出，这是平均相对于电子的速度分布。磁场降低了离子平行于磁场运动的能量损失，同时增强了离子横向运动的能量损失。
Binary collisions between ions and electrons in an external magnetic field are treated in second-order perturbation theory, starting from the unperturbed helical motion of the electrons. For the transfer of relative velocity in a collision, three kinematical regimes are identified, depending on the relative size of the cyclotron radius, the pitch of the helices, and the distance of the closest approach. The magnetic field suppresses the velocity transfer in the transverse direction, but it enhances the longitudinal velocity transfer, provided that the ion velocity itself has a transverse component. In order to relate the velocity transfer to the energy loss of the ions, particular attention must be paid to the nonconservation of the center-of-mass motion in a magnetic field. Hard collisions are accounted for by regularizing the energy transfer at small distances. For ions interacting with monochromatic beams closed expressions for the energy loss can be derived, which are averaged with respect to the velocity distribution of the electrons. The magnetic field reduces the energy loss for ion motion parallel to the magnetic field while it enhances the energy loss for transverse ion motion.