The Langevin equation and its application to grain alignment in molecular clouds
The Langevin equation and its application to grain alignment in molecular clouds
复制标题
朗之万方程及其在分子云中晶粒排列中的应用
DOI：
--
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
J. Flaherty
中科院分区：
文献类型：
--
作者：
W. Roberge;T. Degraff;J. Flaherty
我们描述了一种解决晶粒排列理论问题的新计算方法，该方法使用朗之万方程的布朗旋转数值积分。新方法是完全通用的，因为它可以生成具有任意扩散系数的 Fokker-Planck 方程的解。我们基于颗粒随热动能旋转的特殊假设，推导出带有冰罩的耐火颗粒的扩散系数的准确表达式。我们包括巴尼特弛豫或旋转滞弹性、拉莫尔进动、气体-颗粒碰撞、热蒸发以及顺磁或超顺磁吸收引起的内部耗散的影响
We describe a new computational method for solving problems in grain alignment theory which uses numerical integration of the Langevin equation for Brownian rotation. The new method is completely general in the sense that it generates the solution to a Fokker-Planck equation with arbitrary diffusion coefficients. We derive accurate expressions for the diffusion coefficients of refractory grains with ice mantles, on the ad hoc hypothesis that the grains rotate with thermal kinetic energies. We include the effects of internal dissipation by Barnett relaxation or rotational anelasticity, Larmor precession, gas-grain collisions, thermal evaporation, and paramagnetic or superparamagnetic absorption