ARCHER2 Calendar November 2023

Magnetic field filaments generated by the current filamentation instability

Dr Elisabetta Boella, Lancaster University, Physics Department

One of the long-standing questions in plasmas physics, the science that studies ionized gases called plasmas, regards the origin and evolution of magnetic field in plasmas where such field is initially absent. The question has implications in astrophysics, where the origin of the universe magnetic field is still unknown, and in laboratory plasmas, where magnetic fields spontaneously arise from laser-matter interaction. The Current Filamentation Instability is one of the few mechanisms able to produce a strong magnetic field in an unmagnetised plasma. In the presence of two counter streaming plasma flows and some infinitesimal perturbations, the Lorentz force will deflect the trajectory of the plasma particles in such a way as to cause the formation of net micro-currents and magnetic field filaments. The picture shows the field generated by the instability (blue-green) and ions (orange-red) trapped in the magnetic field filaments. This is the result of a plasma simulation performed with the massively parallel code ECsim on ARCHER2.

This image was published on the November page of the ARCHER2 2023 printed calendar.