On the status of channeling radiation and laser based radiation sources

A unified description of channeling radiation (CR) in oriented crystals (OC) and radiation in the field of an intense plane wave (laser radiation sources - LRS) is proposed in terms of two Lorentz-invariant parameters. The case of planar positron channeling (quasi-channeling) and linearly polarized laser wave is considered in detail up to TeV energies. The crucial difference between LRS and CR is that in the former case both invariants are independent, while in channeling they are linearly related to each other. This leads to a strong limitation on the range of possible values of these invariants in OC. On the other hand, OC make it possible to study QED processes in strong non-uniform external fields.