For two decades, California Institute of Technology professor Paul Beran studied plasma jets and discovered unexpected behavior in “cold” plasma. Initially, he theorized a mechanism for electron acceleration, but simulations showed that some electrons lose little energy as they pass near ions, accelerating continuously. This discovery challenges traditional plasma theory and is important for understanding solar flares and fusion experiments.
Beran and his group have been working in vacuum chambers to generate plasma with magnetically accelerated jets. They found that the jet transitions through several different stages within tens of microseconds. The jet becomes unstable and rapidly expands, causing ripples that accelerate the electrons to high energies, producing X-rays.
The conventional understanding was that jet plasma is too cold to generate high-energy electrons, but the experiments showed otherwise. Beran used computer simulations to discover that some high-energy electrons did appear in cold plasma. These electrons were continuously accelerated in an electric field, reaching enough energy to produce X-rays. This phenomenon could explain high-energy X-rays observed during fusion energy experiments.
This research was published in the journal “Physics of Plasma” and presented at the American Physical Society’s 65th Annual Meeting of the Division of Plasma Physics. Funding for this research was provided by the National Science Foundation and the Air Force Office of Scientific Research.
Source: scitechdaily.com
