Numerical modelling of collisionless perpendicular shocks

DMITRUK, PABLO; GOMEZ, DANIEL; MORALES, LAURA; BERTUCCI, CESAR

Buenos Aires

Congreso; XI LatinAmerican Conference on Space Geophysics (COLAGE); 2018

Asociación Latinoamericana de Geofísica Espacial

Due to the low plasma density, collisionless shocks are ubiquitous in space physics. Examples of this are the bow shocks formed by the solar wind in front of the planets or the termination shock at the heliospheric boundary. The one-fluid magnetohydrodynamic framework provides an adequate description of the large scale structures of the upstream and downstream plasmas, but fails at describing the internal structure of these collisionless shocks. A more comprehensive study of the inner and outer features of collisionless shocks would require the use of kinetic theory. Nonetheless, in the present contribution we show that a complete two-fluid model that includes the role of both ions and electrons, can properly capture some of the features observed in real shocks. For the specific case of perpendicular shocks, i.e. those for which the magnetic field is perpendicular to the shock normal, we numerically solve the one-dimensional two-fluid MHD equations to describe the generation of shocks and their spatial structure across the shock. Our preliminary numerical results show that finite amplitude fast-magnetosonic waves eventually evolve into stationary fast-magnetosonic shocks with a ramp thickness of the order of a few electron inertial lengths. Also, the parallel and perpendicular components of the self-consistent electric field are derived, and their role in accelerating particles is discussed.