Development of Hybrid Plasma Simulations to Study Shock Waves Beyond the Solar System

In 2012, the Voyager 1 space probe left the solar system and began gathering the first ever in situ observations of plasma in the very local interstellar medium (VLISM). Since leaving the solar system, Voyager 1 has twice observed noticeable increases in the background magnetic field, observed on the scale of multiple days (Burlaga & Ness 2016). Some have hypothesized that these observations could be the result of a shock, although the increase in the magnetic field occurs on a much broader scale than is typical for a shock within the solar system. Since plasmas within the solar system are nearly always considered collisionless, we use hybrid plasma simulations to investigate whether weak Coulomb collisionality between ions could result in such a broad shock structure. We first discuss an explicit simulation method that we ultimately show to be unsuitable for our purposes, but which carries valuable lessons nonetheless. Then we propose a more promising semi-implicit simulation scheme and present preliminary results in its development.

This work was supported by the NSF award AGS-1950831. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.