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Lienard-Wiechert Beaming and Synchrotron Lobe

What you are seeing: the angular distribution of radiation from a charge accelerated either parallel to or perpendicular to its velocity. As γ\gamma \to \infty the radiation collimates into a forward cone of opening angle 1/γ\sim 1/\gamma, which is the synchrotron beaming effect. The cyan circle marks the 1/γ1/\gamma opening angle.

Figure 1. Relativistic beaming of the radiation lobe.
γ (Lorentz)3.0
geometry

WHAT TO TRY

  • Raise the Lorentz factor gamma: the radiation lobe collapses from a broad pattern into a tight forward searchlight of half-angle 1/gamma. Relativistic beaming is what makes synchrotron sources so directional.
  • Switch the geometry between acceleration parallel to v and perpendicular to v: the parallel case (linear accelerator) and the perpendicular case (synchrotron) beam into different shapes, both forward-collimated at high gamma.
  • Drag to orbit the camera: the lobe is a 3D solid of revolution about the velocity, so spinning it shows the forward pencil that a distant observer catches only as the beam sweeps past.