Mars as a comet: Solar wind interaction on a large scale

Abstract: Looking at the Mars-solar wind interaction on a larger spatial scale than the near Mars region, the planet can be seen as an ion source interacting with the solar wind, in many ways like a comet, but with a smaller ion source region. Here we study the interaction between Mars and the solar wind using a hybrid model (particle ions and fluid electrons). We find that the solar wind is disturbed by Mars out to 100 Mars radii downstream of the planet, and beyond. On this large scale it is clear that the escaping ions can be classified into two different populations. A polar plume of ions picked-up by the solar wind, and a more fluid outflow of ions behind the planet. The outflow increases linear with the production up to levels of observed outflow rates, then the escape levels off for higher production rates.