Refraction of $e^-$ beams due to plasma lensing at a plasma-vacuum   interface -- applied to beam deflection in a Copper cell with electrical   RF-breakdown plasma
  We formulate a possible description of the deflection of a relativistic $e^-$ beam in an inhomogeneous copper plasma, encountered by the beam when propagating through a accelerating cell that has undergone a high electric-field RF-breakdown. It is well known that an inhomogeneous plasma forms and may last for up to a few micro-seconds, until recombination in an accelerating structure where a field-emission triggers melting and ionization of RF-cell wall deformity. We present a preliminary model for the beam deflection due to collective plasma response based upon the beam density, plasma density and interaction length. 
Aakash A. Sahai, T. C. Katsouleas
physics.acc-ph physics.plasm-ph