Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I am very curious if an easy calculable formula for the bremstrahlung radiation of deeply relativistic, charged particles exists, if they are moving on circular orbit:



  • $P$ is the power of the Bremstrahlung radiation;
  • $E$ is the total kinetic energy of the particles (we are in deeply relativistic case, thus $E\gg{m_0}c^2$);
  • $m_0$ is the total rest mass of the particles;
  • $Q$ is the total charge of the particles;
  • and $r$ is the radius of the orbit.

If a such clean, trivial formula doesn't exist, a link were also okay, where it can be found.

share|improve this question

1 Answer 1

up vote 2 down vote accepted

The radiation from an ultrarelativistic ($v \approx c$) particle on a circular path is called synchotron radiation. The total power radiated from such a particle is $$P = \frac{e^2 a^2}{6\pi \epsilon_0 c}\gamma^4$$ where $a$ is the acceleration and $\gamma$ is the Lorentz factor, $\gamma^2 = 1/(1-v^2/c^2)$.

share|improve this answer
And what is the ultrarelativistic acceleration? $\omega^2r$? –  Peter Horvath May 26 at 19:18
good question: physics.stackexchange.com/q/66839/10531 –  diffeomorphism May 26 at 19:42
For circular motion $a = v^2/r = \omega^2 r$. –  Robin Ekman May 26 at 20:08

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.