Figure 2
From: Plasma channel undulator excited by high-order laser modes
Distribution of the undulator field, test electron trajectories and their on-axis radiation spectrum. (a) The distribution of the transverse electric field normalized by mc 2 k p /e in the space (x, ct) for a fixed position k p ζ = −5π/2. The wakefield is created by two linearly polarized modes m 0 = 0 and m 1 = 1, with intensities a 0 = 0.14 and a 1 = 0.1, spot radius w 0 = 7λ L , and duration τ = 15T L , in a plasma channel with an on-axis density of 0.001n c , where \({n}_{c}={m}_{e}{\omega }_{L}^{2}\mathrm{/(4}\pi {e}^{2})\) is the critical plasma density with ω L the laser frequency. The blue lines represent the trajectories of the test electrons. (b) The corresponding on-axis radiation spectra for the test electrons with different initial transverse positions. Only the first harmonic is considered here.
