一种针对无限n理想气胀模式优化MHD平衡的伴随方法

IF 2.1 3区物理与天体物理 Q2 PHYSICS, FLUIDS & PLASMAS

Journal of Plasma Physics Pub Date : 2023-10-01 DOI:10.1017/s0022377823000995

Rahul Gaur, Stefan Buller, Maximilian E. Ruth, Matt Landreman, Ian G. Abel, William D. Dorland

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引用次数: 0

摘要

我们展示了一种快速的基于伴随的方法来优化托卡马克和恒星平衡对抗压力驱动的不稳定性，称为无限- $n$理想气球模式。我们提出了三个有限的- $\beta$(热压与磁压之比)平衡:一个托卡马克平衡和两个对气球模式不稳定的恒星平衡。利用理想磁流体力学的自伴随性质，构造了一种快速计算理想气胀不稳定性指标特征值变化的方法。使用SIMSOPT优化框架，我们实现了基于梯度的快速伴随优化器，以最小化特征值，并为三个最初不稳定的平衡中的每一个找到稳定的平衡。

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An adjoint-based method for optimising MHD equilibria against the infinite-n, ideal ballooning mode

We demonstrate a fast adjoint-based method to optimise tokamak and stellarator equilibria against a pressure-driven instability known as the infinite- $n$ ideal ballooning mode. We present three finite- $\beta$ (the ratio of thermal to magnetic pressure) equilibria: one tokamak equilibrium and two stellarator equilibria that are unstable against the ballooning mode. Using the self-adjoint property of ideal magnetohydrodynamics, we construct a technique to rapidly calculate the change in the eigenvalue, a measure of ideal ballooning instability. Using the SIMSOPT optimisation framework, we then implement our fast adjoint gradient-based optimiser to minimise the eigenvalue and find stable equilibria for each of the three originally unstable equilibria.

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来源期刊

Journal of Plasma Physics 物理-物理：流体与等离子体

CiteScore

3.50

自引率

16.00%

发文量

106

审稿时长

6-12 weeks

期刊介绍： JPP aspires to be the intellectual home of those who think of plasma physics as a fundamental discipline. The journal focuses on publishing research on laboratory plasmas (including magnetically confined and inertial fusion plasmas), space physics and plasma astrophysics that takes advantage of the rapid ongoing progress in instrumentation and computing to advance fundamental understanding of multiscale plasma physics. The Journal welcomes submissions of analytical, numerical, observational and experimental work: both original research and tutorial- or review-style papers, as well as proposals for its Lecture Notes series.