PI: Prof David Burgess

Figure 1. Snapshots at three different times of the magnetic field magnitude from a simulation modelling a collisionless shock wave interacting with an inflowing turbulent plasma. The turbulent upstream plasma flows from the left towards the right and the compressive shock front propagates towards the left as the simulation progresses. The shock surface is distorted because of the incoming turbulence. Magnetic “eddies”, seen as field enhancements can be seen to pass through the shock being compressed and processed, thus modifying the downstream plasma.

Shock waves in collisionless plasmas are ubiquitous in space, forming at interfaces between fast and slow plasma flows. They form in the solar wind ahead of planetary magnetospheres, in front of coronal mass ejections launched from the Sun, and around supernova remnants. Space plasmas, such as the solar wind flowing out from the Sun, are inherently turbulent, containing complex fluctuations at various scales. However, this pre-existing turbulence has been traditionally neglected in simulations of collisionless shock waves. In this DiRAC project, we study the interaction between plasma turbulence and collisionless shock waves, to understand the controlling nature of turbulence in the dynamics and structure of the shock and its ability to accelerate particles.