Radiation of non-relativistic particle on a conducting sphere and a   string of spheres
  The radiation arising under uniform motion of non-relativistic charged particle by (or through) perfectly conducting sphere is considered. The rigorous results are obtained using the method of images known from electrostatics. 
N.F. Shul'ga, V.V. Syshchenko, E.A. Larikova
physics.acc-ph physics.class-ph