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arXiv 2102.06248physics.plasm-phphysics.comp-ph
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时间积分器不可知电荷守恒有限元PIC

Time Integrator Agnostic Charge Conserving Finite Element PIC

Scott O'Connor, Zane D. Crawford, O. H. Ramachandran, John Luginsland, B. Shanker

摘要:

开发使用有限元基组的粒子单元(PIC)方法,并且没有辅助发散清除方法,直到最近才成为一个长期存在的问题。结果表明,如果使用一致的空间基函数,人们确实可以创建一个方法,是电荷守恒,虽然使用蛙跳时间步进方法。虽然这是一个重大的进步,但蛙跳格式只有条件稳定,时间步长与底层网格密切相关。理想情况下,为了充分利用有限元方法(FEM)的进步,需要一种与时间步进方法无关的电荷守恒PIC方法。这是本文的主要贡献。在下文中,我们将发展这种方法,证明电荷和高斯定律在每个时间步长都离散满足,提供必要的细节来实现这种方法的波动方程有限元法和麦克斯韦求解器有限元法,最后证明其有效性的一套测试问题。该方法将通过单粒子演化、具有空间电荷的非中性束和中性等离子体的绝热膨胀来演示,其中德拜长度已被解决,并且使用了真实的质量比。

英文摘要:

Developing particle-in-cell (PIC) methods using finite element basis sets, and without auxiliary divergence cleaning methods, was a long standing problem until recently. It was shown that if consistent spatial basis functions are used, one can indeed create a methodology that was charge conserving, albeit using a leap-frog time stepping method. While this is a significant advance, leap frog schemes are only conditionally stable and time step sizes are closely tied to the underlying mesh. Ideally, to take full advantage of advances in finite element methods (FEMs), one needs a charge conserving PIC methodology that is agnostic to the time stepping method. This is the principal contribution of this paper. In what follows, we shall develop this methodology, prove that both charge and Gauss' laws are discretely satisfied at every time step, provide the necessary details to implement this methodology for both the wave equation FEM and Maxwell Solver FEM, and finally demonstrate its efficacy on a suite of test problems. The method will be demonstrated by single particle evolution, non-neutral beams with space-charge, and adiabatic expansion of a neutral plasma, where the debye length has been resolved, and real mass ratios are used.

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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