More than 50 years ago, scientists predicted that a laser could generate ions by driving the electrons in plasma to near the speed of light. Plasma typically reflects laser light, but when a strong laser accelerates electrons in the charged gas, plasma can become transparent. During this phenomenon called relativistic transparency, the laser’s energy is transferred to electrons in the plasma, which in turn energizes ions.
Until recently, researchers could only test the fundamental physics of relativistic transparency in computer simulations.
In research published last summer, plasma physicists at Los Alamos, along with collaborators in Germany and the United Kingdom, observed the dynamics of relativistic transparency for the first time.
To do so, they directed the Laboratory’s 200 trillionwatt peak power short-pulse TRIDENT laser at 10- to 100-nanometer thick carbon foils to generate an electron-rich, transparent plasma.
The team’s new understanding of the relativistic transparency can be applied to developing laser-driven particles accelerators, X-ray sources, and ions for cancer treatment.