NSF-BSF: Collaborative Research: Rankine-Hugoniot Conditions Relating the Gyrotropic Regions of Collisionless Shocks in Non-thermal Plasma.

Collisionless shocks are one of the most fundamental nonlinear phenomena in plasma. Magne» tized Collisionless shocks are found at all scales in the Universe: from l—cm scales in lab plasmas to Mpc scales in galaxy clusters. As the most efficient accelerators in the Universe, collisionless shocks produce charged particles with energies up to 1018 eV. Understanding the fundamental physics of Collisionless shocks, especially the structure of the shock transition, is vital for understanding the physics of a large variety of systems in lab and space plasmas as well as the particle acceleration at the shock. One of the central problems of the shock physics is establishing of the relation of the plasma parameters behind the shock from knowledge of these parameters ahead of the shock. Last several decades of the shock studies have shown the crucial importance of kinetic effects for the shock physics, while the classical and the only one theory of thus relation was developed in the 19805 and is based on the treatment of the plasma as a single fluid. The proposed research develops a new theory to describe the transition of the shock structure based on ion kinetics. The methodology is established on the synergy of theory, simulations, and observations: the analytical results of the kinetic approach and test particle analysis are validated using hybrid simulations and further compared to observations of heliospheric shocks at large variety of the missions in the solar system. The result of the study has far—reaching implications for the fundamental plasma physics of strongly nonlinear phenomena and for mechanisms of charged particle acceleration by shock waves in the heliosphere as well as in the Universe.