Solar flares and coronal mass ejections send out shock waves that reverberate through our solar system. But shock waves through plasma – the ionized, high-energy particles making up the solar wind – do not behave like our typical terrestrial ones. Instead of traveling through collisions between particles, these astrophysical shock waves are driven by interactions between moving, charged particles and magnetic fields.
A driving burst of plasma accelerated into ambient plasma creates electromagnetic forces that accelerate ambient ions to supersonic speeds, pushing the shock wave onward even without particles directly colliding. Thus far, piecing together the physics of these interactions has been a challenge because spacecraft are limited in what and where they can measure. But a group here on Earth has now recreated and observed some of this process in the lab. (Image credit: NASA Solar Dynamics Observatory; research credit: D. Schaeffer et al.; via phys.org)