Fig. 1. A comparison of measured electron beam energies in laser wakefield acceleration with the energy scaling as a function of the operating plasma density for (a) the self-guided case in the bubble regime at laser wavelengths of 800 nm (solid line) and 1057 nm (dashed line) and (b) the channel-guided case in both the quasi-linear regime (dashed line) and the bubble regime (solid line). The experimental data are plotted with filled squares for and the open square for in (a), and with filled circles for in (b).

Fig. 2. Electron beam energy spectra obtained from the experiment^[6], where a 212-TW, 60-fs laser pulse is focused on a spot radius of producing at the entrance of a gas jet for three cases consisting of (a) a 4-mm long single stage with , (b) a 10-mm long single stage with and (c) two stages comprising a 4-mm long injector with and a 10-mm long accelerator with .

Table 1. Parameters of experiments on GeV-class laser wakefield acceleration.

Table 2. Design parameters for 10-GeV-level laser plasma accelerators in comparison with the results of the 3D PIC simulation^[16]. Case A stands for the self-guided case in the bubble regime, designed by the formulas given in Section 4.1, case B for the self-guided case in the bubble regime, designed by the formulas given in Section 4.2, case C for the channel-guided case in the quasi-linear regime, designed by the formulas given in Section 4.3, and case D for the self-guided case in the bubble regime at 40 GeV, designed by the formulas given in Section 4.1.