Wiktionary
beamstrahlung
n. (context physics English) The radiation from one beam of charged particles in a storage ring or linear collider caused by its interaction with the electromagnetic field of the other beam. Coined by J. Rees in 1978. "Limitations on Performance of e+ e- Storage Rings and
Wikipedia
Beamstrahlung
' Beamstrahlung' (from beam + bremsstrahlung ) is the radiation from one beam of charged particles in storage rings or linear colliders caused by its interaction with the electromagnetic field of the other beam. Coined by J. Rees in 1978.
It is a source of radiation loss in colliders, more specifically a type of synchrotron radiation.