Abstract-Beam dynamics in THz dielectric-loaded waveguides for the AXSIS project

T Vinatier1, R W Assmann1, U Dorda1, F Lemery2 and B Marchetti1

http://iopscience.iop.org/article/10.1088/1742-6596/874/1/012042/meta;jsessionid=C02E64AFEB4527A91F3E6D34A998989A.c2.iopscience.cld.iop.org

In this paper, we investigate with ASTRA simulations the beam dynamics in dielectric-loaded waveguides driven by THz pulses, used as linac structure for the AXSIS project. We show that the bunch properties at the linac exit are very sensitive to the phase velocity of the THz pulse and are limited by the strong phase slippage of the bunch respective to it. We also show that the bunch properties are optimized when low frequencies (< 300 GHz) are used inside the linac, and that the longitudinal focal point can be put several tens of cm away from the linac exit thanks to ballistic bunching. However, a strong asymmetry in the bunch transverse sizes remains for which a solution is still to be found.