Electron self-injection and acceleration in a hollow plasma channel driven by ultrashort intense laser pulses
Deng Suhui, Liu Mingping
       

The energy distribution of electrons as a function of the divergence angle at t= 0.5 ps (a), 1.23 ps (b), 3.5 ps (c), and 5.2 ps (d), respectively. The electron density is in arbitrary unit.