Effects of Initial Conditions on Energy Distribution of Suprathermal Electrons in Interaction of Intense Ultrashort Laser Pulse with a Preplasma

Relativistic momentum and energy equations of electrons in an intense laser field are derived with Hamilton-Jacobi equation. For initial electrons in non-equilibrium or Maxwellian equilibrium distributions in preplasmas, suprathermal electron energy distributions are obtained analytically and numerically. The calculation results agree well with the experiments.