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arXiv 1209.5548math.NAcs.NA
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微磁学中的多尺度建模:解的存在性与数值积分

Multiscale modeling in micromagnetics: existence of solutions and numerical integration

Vienna University of Technology(维也纳工业大学)

Florian Bruckner, Michael Feischl, Thomas Führer, Petra Goldenits, Marcus Page, Dirk Praetorius, Michele Ruggeri, Dieter Suess

AI总结:

本文针对微磁学中的多尺度模型,在非线性材料律假设下证明了弱解的存在性,并提出了线性隐式数值积分器以保证有限元解的弱收敛性。

摘要:

从自旋电子器件、巨磁阻传感器到磁存储设备等各种应用,都包含不同长度尺度上的磁性部件。由于Landau-Lifshitz-Gilbert方程(LLG)将介质中的最大单元尺寸限制在交换长度内,因此用这种方法模拟宏观部件在数值上并不吸引人。另一方面,静磁Maxwell方程不限制单元尺寸,但无法准确描述短程交换相互作用。两种方法的结合允许通过LLG描述微磁区域内的磁畴,并通过使用Maxwell方程的非线性材料律考虑宏观部件。在我们的工作中,我们证明了在非线性材料律的某些假设下,这种多尺度版本的LLG存在弱解。我们的证明是建设性的,因为我们为多尺度模型提供了一个线性隐式数值积分器,使得数值可计算的有限元解(至少对于子序列)弱$H^1$收敛于一个弱解。

英文摘要:

Various applications ranging from spintronic devices, giant magnetoresistance sensors, and magnetic storage devices, include magnetic parts on very different length scales. Since the consideration of the Landau-Lifshitz-Gilbert equation (LLG) constrains the maximum element size to the exchange length within the media, it is numerically not attractive to simulate macroscopic parts with this approach. On the other hand, the magnetostatic Maxwell equations do not constrain the element size, but cannot describe the short-range exchange interaction accurately. A combination of both methods allows to describe magnetic domains within the micromagnetic regime by use of LLG and also considers the macroscopic parts by a non-linear material law using the Maxwell equations. In our work, we prove that under certain assumptions on the non-linear material law, this multiscale version of LLG admits weak solutions. Our proof is constructive in the sense that we provide a linear-implicit numerical integrator for the multiscale model such that the numerically computable finite element solutions admit weak $H^1$-convergence (at least for a subsequence) towards a weak solution.

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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