Extreme energy transformations and transfers in astrophysical and laboraasmas

The transport and conversion of vast amounts of energies in different forms is the key aspect of almost all major events in laboratory plasma experiments, in our solar system and in more remote astrophysical systems. Nevertheless, energy transfer and transformation mechanisms in plasmas are still riddled with many fundamental challenges due to their intrinsic multi-scale and multi-faceted nature. Multi-scale aspects come in when trying to bridge the enormous gap from kinetic, essentially (ensemble) particle behavior at the smallest scale to the large scale magnetohydrodynamic regime, as well as when making definite cause-and-effect inferences between dynamics occurring in vastly separated plasma configurations (e.g. the Sun-Earth system in space weather). Many of these multi-faceted energy transformations (i.e. displaying a fair variety in transfer channels) can be witnessed up close in laboratory experiments and in the highly structured solar atmosphere and throughout the heliosphere, or reach us in observable electromagnetic form from further reaches of the universe.

Our project focuses especially on the following cases:

• The Sun-Earth system and similar planetary systems in which magnetic energy is constantly released into particle energy leading to the hot stellar atmospheres. Our ambitions encompass modeling of solar/stellar-planetary relations, as well as studies of the multi-faceted nature of the highly structured solar atmosphere, incl. realistic solar dynamics studies, connecting flux emergence and magneto-convectively mediated flux reshuffling scenarios at photospheric layers to small-scale physics in reconnection sites throughout the chromospheric to coronal layers, while capturing the large-scale magnetic topology reconfigurations. These give rise to large energy and matter release (flares, coronal mass ejections) and lead to extremely energetic particles creating a severe risk for space exploration.
• High energy phenomena associated with more exotic astrophysical environments such as pulsar winds, micro-quasar systems and Active Galactic Nuclei associated jets, responsible for accelerating some of the most energetic particles in the universe. In these environments, up to ultra-relativistic plasma conditions conspire to transform, transport and release massive amounts of energy.
• Laser-produced or magnetically confined plasmas in which wave-particle interactions and instabilities drive the transfer of energy between field and thermal particles or energetic beams. Examples of these include long-lived magnetic fields produced by laser interactions with solid targets, and Kelvin-Helmholtz instabilities produced in shear-flows, the latter an important mechanism for cross-field particle transport in both space and laboratory contexts.

These multi-scale challenges enforce the use of clever means to couple (different) plasma models in hierarchical ways, and they have been the motivating principle in our continuing efforts into advanced plasma simulations. These meanwhile incorporate the results from our previous GOA project (GOA2009-009), viz. automated mesh refinement (AMR) approaches, multi-physics coupling schemes, as well as multi-scale multi-domain innovations.