柱坐标下的快速椭圆求解器与库仑碰撞算子
Fast elliptic solvers in cylindrical coordinates and the Coulomb collision operator
AI总结:
本文提出一类新的快速求解器,用于柱坐标下具有自由空间辐射条件的可分离椭圆偏微分方程,通过结合径向积分方程方法和角向傅里叶方法实现高精度,并应用于电离气体动力学模型中库仑碰撞算子的评估。
摘要:
本文描述了一类新的快速求解器,用于柱坐标$(r,θ,z)$下具有自由空间辐射条件的可分离椭圆偏微分方程。通过将径向变量$r$中的积分方程方法与$θ$和$z$中的傅里叶方法相结合,我们表明可以在控制势及其导数中实现高阶精度。在关于$z$的傅里叶变换中出现了一个弱奇异性,该奇异性通过专用求积法处理。我们展示了如何将这些求解器应用于电离气体动力学模型中库仑碰撞算子的评估。
英文摘要:
In this paper, we describe a new class of fast solvers for separable elliptic partial differential equations in cylindrical coordinates $(r,θ,z)$ with free-space radiation conditions. By combining integral equation methods in the radial variable $r$ with Fourier methods in $θ$ and $z$, we show that high-order accuracy can be achieved in both the governing potential and its derivatives. A weak singularity arises in the Fourier transform with respect to $z$ that is handled with special purpose quadratures. We show how these solvers can be applied to the evaluation of the Coulomb collision operator in kinetic models of ionized gases.
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