During lightning storms previously observed by spacecraft, energetic electrons moving toward the craft slowed down and produced gamma rays. That actually sound

During lightning storms previously observed by spacecraft, energetic electrons moving toward the craft slowed down and produced gamma rays. That actually sounds like bremsstrahlung x-rays, not gamma rays. They have very different energy spectra due to their origin. Although you can also slow down the electrons by first producing an electron-positron pair, and then the positron will decay into two gammas.