Investigating multi-moment fluid model closures using particle-in-cell simulations

The global magnetosphere model OpenGGCM has been extended to support multi-moment fluid models as an alternative to conventional MHD. These models are derived without approximation by taking velocity space moments of the Vlasov equation for each species, while keeping the full Maxwell equations. However, the hierarchy of fluid equations needs to be truncated, which is currently achieved by postulating closures for the heat flux.

In this work, we will investigate magnetic reconnection in 2-d and 3-d simplified geometries, covering both symmetric and asymmetric cases. We will examine the actual heat fluxes, calculated from the particle distributions in fully kinetic particle-in-cell simulations and compare them to the simplified models used in the existing five-moment and ten moment fluid model closures, In particular, we will look at the "typical instability wavelength" free parameters that go into the ten-moment closure.