# When (Exactly) Does Bremsstrahlung Radiation Occur?

Regarding the Bremsstrahlung Radiation emitted when a charged particle curves inside a uniform magnetic field; Is there a way of calculating the angle through which the charged particle will precess before emitting the first quantum of radiation? Also, is there a way of determining the angle through which the charged particle will precess between the first and second emissions of radiation?

My investigations revealed only what I think are the angles of emission relative to the tangent of the curve here.

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There is surely no definite angle, only some probability distribution. I think that number of emitted photons (by a given time) is distributed according to Poisson, in each wavelength. You can (classically) compute the emitted spectrum, and convert it to averaged particles/second for each wavelength. Then use this and the form of the probability distribution to find the parameters of the distribution, so that you can e.g. compute the expectation values of this angles. – Peter Kravchuk May 18 '13 at 21:14
To emphasize what Peter has said, this is a quantum mechanical process. Of course it is ruled by probabilities. – dmckee May 18 '13 at 21:24
Okay, so we all agree this is a probabilistic process. That doesn't invalidate the question. What are the expected values of these angles, as a function of field strength, particle mass, etc? – Chris White May 18 '13 at 23:23
See Prof. Lewin's free MIT course, 8.03, specifically on accelerated charges. I have not seen a better video derivation of Larmor's formula, than by Lewin. – JamalS Jun 1 '14 at 18:18