arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1609.09862math.NAcs.NA
收藏

基于Legendre-Fourier谱方法的Vlasov-Poisson系统的精确守恒律方法

A Legendre-Fourier spectral method with exact conservation laws for the Vlasov-Poisson system

Los Alamos National Laboratory(洛斯阿拉莫斯国家实验室);Istituto di Matematica Applicata e Tecnologie Informatiche, Consiglio Nazionale delle Ricerche (IMATI-CNR)(应用数学与信息技术研究所,意大利国家研究委员会 (IMATI-CNR));KTH Royal Institute of Technology(瑞典皇家理工学院)

G. Manzini, G. L. Delzanno, J. Vencels, S. Markidis

AI总结:

本文提出了一种L2稳定的谱方法,用于求解无碰撞等离子体的Vlasov-Poisson模型,通过Legendre和Fourier基函数展开速度和空间依赖性,并证明了质量、动量和能量的精确守恒。

摘要:

我们提出了一个L2稳定的谱方法的设计和实现,用于离散化无碰撞等离子体的Vlasov-Poisson模型。速度和空间依赖性通过基于Legendre和Fourier基函数的截断谱展开来解决。Poisson方程通过Fourier展开来解决。由此得到的常微分方程组通过隐式二阶准确的Crank-Nicolson时间离散化进行离散化。Vlasov和Poisson方程之间的非线性依赖性通过Jacobian-Free Newton-Krylov方法在任意时间周期内迭代求解。本文分析了所得到Legendre-Fourier模型的主要守恒律的结构,例如质量、动量和能量,并证明它们在半离散和离散设置中被精确满足。L2稳定性通过在速度域边界处对分布函数的边界条件进行适当惩罚项的离散化来保证。惩罚项对守恒性质的影响通过理论和数值方法进行研究。还提出了一种不影响质量、动量和能量守恒的惩罚项的实现并进行了研究。在离散模型中引入了一个碰撞项以控制丝状效应,但不影响系统的守恒性质。标准测试问题的数值结果展示了该方法的性能。

英文摘要:

We present the design and implementation of an L2-stable spectral method for the discretization of the Vlasov- Poisson model of a collisionless plasma in one space and velocity dimension. The velocity and space dependence of the Vlasov equation are resolved through a truncated spectral expansion based on Legendre and Fourier basis functions, respectively. The Poisson equation, which is coupled to the Vlasov equation, is also resolved through a Fourier expansion. The resulting system of ordinary differential equation is discretized by the implicit second-order accurate Crank-Nicolson time discretization. The non-linear dependence between the Vlasov and Poisson equations is iteratively solved at any time cycle by a Jacobian-Free Newton-Krylov method. In this work we analyze the structure of the main conservation laws of the resulting Legendre-Fourier model, e.g., mass, momentum, and energy, and prove that they are exactly satisfied in the semi-discrete and discrete setting. The L2-stability of the method is ensured by discretizing the boundary conditions of the distribution function at the boundaries of the velocity domain by a suitable penalty term. The impact of the penalty term on the conservation properties is investigated theoretically and numerically. An implementation of the penalty term that does not affect the conservation of mass, momentum and energy, is also proposed and studied. A collisional term is introduced in the discrete model to control the filamentation effect, but does not affect the conservation properties of the system. Numerical results on a set of standard test problems illustrate the performance of the method.

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。

↑