arXiv subjects

Emil Poulsen

Publications and source records attributed to Emil Poulsen.

3 recordsLinked to original sources

arXiv2026

Geometric numerical discretization of electromagnetic quasineutral models

In this work, the geometric electromagnetic Particle-in-Cell (PIC) framework, GEMPICX, is extended to solve the quasineutral, fully kinetic Vlasov-Maxwell equations on dual grids using mimetic finite differences. The discrete action principle is derived, taking into account the duality between the grids. The temporal derivative of the electric field does not directly appear in the dynamical system for the quasineutral model. Hence, a discretized curl-curl equation is used to implicitly obtain the electric field at every time-step. This also circumvents the need to obtain electric potentials. A Lagrange multiplier is used to maintain the discretized divergence of the current density at machine zero.

physics.plasm-ph↗

arXiv2026

Geometric numerical discretization of a quasineutral hybrid model of drift-kinetic electrons and fully kinetic ions

We extend the geometric electromagnetic particle-in-cell (PIC) framework, GEMPICX, to solve the quasineutral hybrid Vlasov-Maxwell equations with drift-kinetic electrons and fully kinetic ions. A structure-preserving finite difference method that employs dual grids is used. The discrete action principle for the hybrid model is derived, using the dual nature of the grids. The dynamical system for this hybrid quasineutral model does not explicitly involve the temporal evolution term for the electric field. A curl-curl equation is therefore used to implicitly obtain the component of the electric field that is parallel to the background magnetic field, at every timestep. The perpendicular component of the electric field is obtained using the quasineutral Ampere's equation without the displacement current, combined with the definition of the current in the drift-kinetic model. The discretized versions of the electric field equations are large, sparse linear systems. A fully explicit time-stepping scheme as well as two implicit-explicit (IMEX) schemes are tested. The numerical model is validated by verifying the various waves obtained from the dispersion relation.

physics.plasm-ph↗

arXiv2025

A geometric Particle-In-Cell discretization of the drift-kinetic and fully kinetic Vlasov-Maxwell equations

In this paper, we extend the geometric Particle in Cell framework on dual grids to a gauge-free drift-kinetic Vlasov--Maxwell model and its coupling with the fully kinetic model. We derive a discrete action principle on dual grids for our drift-kinetic model, such that the dynamical system involves only the electric and magnetic fields and not the potentials as most drift-kinetic and gyrokinetic models do. This yields a macroscopic Maxwell equation including polarization and magnetization terms that can be coupled straightforwardly with a fully kinetic model.

physics.plasm-ph↗