How do cosmic-ray electrons create synchrotron radiation?

Cosmic-ray electrons generate synchrotron radiation when they travel at speeds close to the speed of light and their paths are altered by a magnetic field.1

As these high-energy electrons move through the galactic magnetic field, they are forced into spiral paths. Because the particles are being accelerated—specifically, because their velocity vectors are constantly changing direction due to the magnetic force—they emit electromagnetic energy. This radiation is characterized as nonthermal and is typically highly polarized and continuous.213

The intensity and frequency of the resulting synchrotron radiation are directly dependent on the strength of the magnetic field and the energy of the electrons; higher energy levels and stronger magnetic fields result in greater intensity and higher frequencies of emitted radiation. This process is a key method by which astronomers detect and study cosmic-ray electrons, as the radiation can be observed by radio telescopes and has been confirmed in sources such as supernova remnants like the Crab Nebula.12