| The effects of radiation reaction on ultra relativistic electron beam dynamics are studied in a laser plasma-based accelerator using an elec- trostatic laser-produced wakefield model. The electrons of the beam undergo transverse betatron oscillations due to the strong focusing force of the plasma channe. These oscillations force the electrons to emit betatron radiation. The corresponding radiation damping expels some of the radiating electrons from the accelerating bucket, which in turn leads to a huge decrease in the transverse emittance of the electron beam. Moreover, the average transverse radius of the beam depends on the critical energy Ecrit (the value of energy at which ra- diation damping and accelerating terms become equal) of the beam in the laser wakefield of a given plasma density. If the energy of the beam increases the average transverse radius decreases, which also de- creases the emittance of the beam. It is found that in the wakefield the beam continues to gain energy. This emittance decreasing tech- nique is different from Thomson cooling and emittance reduction in undulator magnet where the beam is decelerated. |
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