On the validity of the guiding-center approximation in the presence of strong magnetic gradients
On the validity of the guiding-center approximation in the presence of strong magnetic gradients
复制标题
强磁梯度下引导中心近似的有效性
DOI：
10.1063/1.4981217
复制
发表时间：
2017
影响因子：
2.2
通讯作者：
A. Brizard
中科院分区：
文献类型：
--
作者：
A. Brizard
带电粒子在具有恒定磁场梯度的非均匀直磁场中的运动可以用椭圆函数精确求解。讨论了该问题与引导中心近似之间的联系。结果表明，对于这个问题，高阶引导中心理论的预测与轨道平均粒子运动非常吻合，并且远远超出标准引导中心极限 ϵeqρ/L<1，其中 ρ 是回转运动长度尺度，L 是磁场梯度长度尺度。
The motion of a charged particle in a nonuniform straight magnetic field with a constant magnetic-field gradient is solved exactly in terms of elliptic functions. The connection between this problem and the guiding-center approximation is discussed. It is shown that, for this problem, the predictions of higher-order guiding-center theory agree very well with the orbit-averaged particle motion and hold well beyond the standard guiding-center limit ϵ≡ρ/L≪1, where ρ is the gyromotion length scale and L is the magnetic-field gradient length scale.