Shielded Coherent Synchrotron Radiation and Its Effect on Very

Shielded coherent synchrotron radiation is discussed for two cases: (1) a beam following a circular path midway between two parallel conducting plates, and (2) a b earn circulating in a toroidal chamber. Wake -fields and the energy radiated are computed for both cases. Under conditions like those of the high-energy bunch compressor of the Next Linear Collider (NLC), in which bunches as short as 40 microns are contemplated, the shielded coherent radiated power is estimated to be small compared to the incoherent power, but can still amount to a few hundred KeV over the compressor arc.