Studying self-consistent collisional plasma dynamics with electromagnetic Particle in Cell simulations

Existing theories of collisional dynamics in plasmas are largely based on assumptions that do not hold for plasmas outside of local thermodynamic equilibrium and in strongly driven regimes. Previous work using first-principle electrostatic Particle-in-Cell (PIC) simulations has demonstrated that the PIC algorithm can self-consistently model collisional dynamics without requiring additional modules [1,2]. This is achieved by resolving the mean interparticle distance, which allows to correctly resolve the interparticle fields that mediate collisional interactions. As a result, these simulations use less than one particle per cell on average, and the macro-particles represent the real particles of the system. In this work, we use 3D electromagnetic PIC simulations to explore self-consistent collisional plasma dynamics. We discuss some of the numerical challenges faced when running self-consistent simulations in this regime and compare the observed collisional dynamics with existing theory. Lastly, we will discuss opportunities for how the data produced in such simulations can be used to design improved collisional operators for plasma dynamics in regimes where the existing theory does not hold.

[1] C. Decker et al, Phys. Plasmas 1, 4043–4049 (1994)

[2] M. D. Acciarri et al, Plasma Sources Sci. Technol. 33, 035009 (2024)