Effects of correlation in transition radiation of super-short electron bunches

The effect of correlations between electrons in transition radiation is investigated. The correlation function is obtained with help of the approach similar to the Debye-Hückel theory. The corrections due to correlations are estimated to be near 2-3% for the parameters of future projects SINBAD and FLUTE for bunches with extremely small lengths (∼1-10 fs). For the bunches with number of electrons about ∼2.5∗1010 and more, and short enough that the radiation would be coherent, the corrections due to correlations are predicted to reach 20%.