Dynamical Low-Rank Approximation of the Vlasov-Poisson Equation with Piecewise Linear Spatial Boundary

Core Concepts

The core message of this article is to develop a projector splitting scheme for dynamical low-rank approximation (DLRA) of the Vlasov-Poisson equation that can handle inflow boundary conditions on spatial domains with piecewise linear boundaries.

Abstract

The article presents a dynamical low-rank approximation (DLRA) approach for numerically solving the Vlasov-Poisson equation, which models the time evolution of an electron density in a collisionless plasma. The standard DLRA method uses a splitting of the tangent space projector according to the separated variables of space and velocity. However, a less studied aspect is the incorporation of boundary conditions in the DLRA model.
The key highlights and insights are:

A variational formulation of the projector splitting is proposed that allows handling inflow boundary conditions on spatial domains with piecewise linear boundaries.
The effective equations for the low-rank factors are derived in the form of Friedrichs' systems (systems of hyperbolic equations in weak formulation) that respect the boundary conditions without violating the tensor product structure.
A finite element discretization is developed, leading to discrete equations that can be solved numerically using stabilized finite elements.
The standard projector splitting integrator as well as a rank-adaptive unconventional integrator are considered and implemented.
Numerical experiments demonstrate the feasibility of the proposed approach for solving the Vlasov-Poisson equation with piecewise linear spatial boundaries.

Stats

The article does not contain any explicit numerical data or metrics. It focuses on the theoretical development and derivation of the numerical schemes.

Quotes

None.

Key Insights Distilled From

Dynamical low-rank approximation of the Vlasov-Poisson equation with piecewise linear spatial boundary

by Andr... at arxiv.org 04-11-2024

https://arxiv.org/pdf/2303.01856.pdf

Deeper Inquiries

How can the proposed approach be extended to handle more general spatial domain geometries beyond piecewise linear boundaries

To extend the proposed approach to handle more general spatial domain geometries beyond piecewise linear boundaries, one could consider using more sophisticated discretization techniques such as the discontinuous Galerkin method. This method allows for the use of non-conforming meshes and can handle complex geometries with greater flexibility. By employing higher-order basis functions and allowing for discontinuities at element boundaries, the discontinuous Galerkin method can effectively capture the geometry of irregular domains. Additionally, adaptive mesh refinement strategies can be implemented to dynamically adjust the mesh resolution in regions of interest, further enhancing the accuracy and efficiency of the numerical simulations. Overall, by incorporating advanced numerical methods tailored to specific geometries, the proposed approach can be extended to handle a wide range of spatial domain shapes and complexities.

What are the theoretical guarantees, such as existence and uniqueness of weak solutions, for the continuous formulation of the projector splitting scheme with the incorporated boundary conditions

The theoretical guarantees for the continuous formulation of the projector splitting scheme with incorporated boundary conditions involve ensuring the existence and uniqueness of weak solutions to the Vlasov-Poisson equation. In the context of the projector splitting integrator, the weak formulation of the boundary conditions allows for the incorporation of inflow boundary conditions on spatial domains with piecewise linear boundaries. By formulating the problem in a variational framework and utilizing projector splitting techniques, the scheme aims to preserve the tensor product structure of the low-rank approximation while enforcing the boundary conditions. The existence and uniqueness of weak solutions can be established through appropriate functional analysis techniques, ensuring that the numerical scheme provides a well-posed and reliable approach for simulating the Vlasov-Poisson equation with spatial boundary constraints.

Can the proposed DLRA framework be adapted to ensure conservation properties, such as mass, momentum and energy, in the numerical solution of the Vlasov-Poisson equation

The proposed DLRA framework can be adapted to ensure conservation properties, such as mass, momentum, and energy, in the numerical solution of the Vlasov-Poisson equation. Conservation laws are crucial for maintaining the physical accuracy of the simulation and are typically enforced through modified Galerkin conditions. By incorporating these conservation properties into the numerical integrator, the DLRA scheme can preserve important physical quantities throughout the simulation. Techniques such as modified projection operators and additional constraints can be introduced to enforce conservation laws and ensure that the numerical solution accurately reflects the underlying physics of the system. By incorporating conservation properties into the DLRA framework, the numerical simulations can provide more accurate and reliable results for the Vlasov-Poisson equation.