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arXiv 2108.13622math.NAastro-ph.IMcs.NAphysics.comp-ph
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电阻磁流体动力学指数积分器:无矩阵Leja插值和有效的自适应时间步进

Exponential Integrators for Resistive Magnetohydrodynamics: Matrix-free Leja Interpolation and Efficient Adaptive Time Stepping

Pranab Deka, Lukas Einkemmer

摘要:

提出了一种新的电阻磁流体动力学(MHD)方程的时间积分算法。该方法是基于指数Rosenbrock计划与Leja插值相结合。它自然地保留了高斯定律的磁性,是不受限制的稳定性观察明确的方法。在设计指数积分器和有效计算所需矩阵函数方面取得了显著进展。然而,采用它们在现实的物理场景的MHD模拟需要一个矩阵的自由实现。我们展示了如何一个有效的算法的基础上Leja插值,只使用右手边的微分方程(即矩阵自由),可以构建。我们进一步证明,它优于Krylov为基础的指数积分,以及显式和隐式方法使用测试模型的磁重联和开尔文-亥姆霍兹不稳定性。此外,自适应步长策略,提供了优异的和可预测的性能,特别是在宽松的中间容忍制度,往往是在实际应用中的重要性,被采用。

英文摘要:

We propose a novel algorithm for the temporal integration of the resistive magnetohydrodynamics (MHD) equations. The approach is based on exponential Rosenbrock schemes in combination with Leja interpolation. It naturally preserves Gauss's law for magnetism and is unencumbered by the stability constraints observed for explicit methods. Remarkable progress has been achieved in designing exponential integrators and computing the required matrix functions efficiently. However, employing them in MHD simulations of realistic physical scenarios requires a matrix-free implementation. We show how an efficient algorithm based on Leja interpolation that only uses the right-hand side of the differential equation (i.e. matrix free), can be constructed. We further demonstrate that it outperforms Krylov-based exponential integrators as well as explicit and implicit methods using test models of magnetic reconnection and the Kelvin--Helmholtz instability. Furthermore, an adaptive step-size strategy that gives excellent and predictable performance, particularly in the lenient- to intermediate-tolerance regime that is often of importance in practical applications, is employed.

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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