High-energy X-ray bursts from low-energy plasma

Solar flares shouldn’t produce X-rays, but they do. Why? The one-size-fits-all approach to electron collisions misses a lucky few that lead to an intense X-ray burst. Scientists thought there were too many electron-scattering collisions in such cold plasmas for electrons to be accelerated to high energy and radiate X-rays. While most of the electrons in a cold plasma collide before they can accelerate, it’s possible that a few don’t collide. These particles are like warriors who endure a sequence of deadly battles but survive each encounter and develop experience to have a better chance of surviving the next one.