Fig. 1. (Color online) Sketch map of fusion targets designed for (a) normal ICF Programs and (b) in our scheme.

Fig. 2. (Color online) Energy spectra (a) and longitudinal phase space distribution (b) of the energetic electrons generated by a ${\rm CO}_{2}$ laser pulse (only electrons with energy larger than 500 keV are presented). The blue fitting line in (a) gives an electron temperature of 1.4 MeV.

Fig. 3. (Color online) Longitudinal momentum of background plasma electrons at the beam position (marked by the red dashed curve) (a). Density distribution of electron beam after propagating 1 mm in the plasma of density $1 \times 10^{19}\ {\rm cm}^{-3}$ (b) and $5 \times 10^{19}\ {\rm cm}^{-3}$ (c). The energy spectrum of electron beam at propagating distance $x =0$ mm (black curve), $x = 1$ mm in the $1 \times 10^{19}\ {\rm cm}^{-3}$ plasma (blue curve), and $x = 1$ mm in the $5 \times 10^{19}\ {\rm cm}^{-3}$ plasma (red curve) (d).