Hierarchical Coupling

The following videos provide an impression of the hierarchical coupling employed by the muphyII framework:

Video 1: Coupled Biskamp-Welter vortex decaying turbulence simulation.
left: current density magnitude.
right: model refinement grid (orange grid), ten-moment regions (white) and Hybrid regions (grey). Cells with current density larger than half Alfvén speed (the refinement threshold) are colored black.
Note how the Vlaosv region is dynaically following the current sheets.

Video 2: Coupled Geospace Environmental Modelling (GEM) challenge simulation with criteria evaluation depicted.
left column: out-of-plane electron (top) and ion (bottom) velocities.
right column: preferred models based on predefined threshold values (red: Vlasov; blue: ten-moment fluid; yellow: five-moment fluid).
Actual models used in each region is the lowest possible model in the muphyII model hierarchy based on the depicted threshold recommendations. Time is shown in the top left corner.

Video 3: Early coupled Geospace Environmental Modelling (GEM) challenge simulation with refinement criterion based on temperature gradient.
Fully kinetic Vlasov region is coupled to a two-fluid ten-moment region. Initial models are prescribed.
The temperature gradient criterion requires comparably large kinetic regions.

Video 4: Velocity distribution in a kinetic reconnection snapshot.
Top: Out-of plane electron velocity. A red marker moves along the inflow and outflow.
Bottom: Two isosurfacec of the electron velocity distribution function at the position of the red marker
Note how closely the distribution function resembles Maxwellian outside the diffusion region