Computational Plasma Physics

Modelling the interaction of laser or particle beams with fully ionized, hot, dense matter poses a considerable computational challenge owing to the extreme relativistic intensities created by the laser, interposed with highly contrasting material properties in the vicinity of the interaction. Simulations in this domain are indispensable for gaining physical insight into absorption and transport phenomena in high intensity laser interactions, providing theoretical support for a number of important applications currently pursued worldwide, such as the Fast Ignitor Fusion concept, femtosecond X-ray sources, and compact ion accelerators.

At JSC we employ different methods to model the interaction of laser plasma interactions. One is the use of three-dimensional mesh-free plasma simulation (PEPC) to investigate topical issues in high energy-density plasma physics from a fresh perspective, including collective heating and 'whole-target' transport of fast electrons, the origin and acceleration mechanisms of MeV protons, Gigagauss magnetic field generation, the effects of surface inhomogeneity on high harmonic generation, and the early plasma formation in tokamaks. The fully Lagrangian, collisional kinetic approach offered by this model presents a new paradigm in computational plasma physics. This is complemented by the more conventional and proven technique of Particle-in-Cell (BOPS, JuSPIC, EPOCH, KLAPS) simulations.

Furthermore, the development of fast and scalable algorithms for large-scale particle simulations is an important part of our plasma-physical research.

Laser-Produced Light Sources

Simulations in a relativistic, highly non-linear regime of Laser-plasma interaction make it possible to invesitgate light-sources, e.g. for X-rays. Those provide insight into ultrafast, time-resolved structural dynamics of materials, such as chemical reactions or phase transitions. We employ Particle-in-Cell simulations to reproduce the whole process from high energy electron generation to the emission of X-rays.

Laser Particle Acceleration

High intensity lasers and their interaction with plasmas promise to enable table-top particle accelerators for a wide range of industrial and medical applications. We create detailed 3D and 2D simulations to study the particle evolution.

Plasma Formation in Magnetic Fusion Devices

Magnetic plasma confinement can never be ideal and is inherently complex. This already starts with the formation of the initial plasma, is later compromised by the necessity to rid the burning plasma of ash products and replace the hydrogen fuel and has to include edge effects leading to a powerful exchange of matter between the plasma and the solid container. Overall, the physics demands multi-scale, multi-physics modelling.

Algorithms for Computational Plasma Physics

With the recent advent of many- core architectures and new accellerator units, additional layers of parallelism beyond MPI have to be added to existing scientific codes for making efficient use of the available computing power.