Electron acceleration by static and oscillating electric fields produced in the interaction between femtosecond laser pulses and solid targets

The interaction of modest, femtosecond (fs) laser pulses with solid targets is studied with particle-in-cell (PIC) simulations. A bi-temperature distribution of hot electrons is found. The first hot electron temperature can be attributed to the resonance absorption of the laser field, whereas the second hot electron temperature is identified to be due to the combined acceleration by the static electric field in front of the target and by the laser induced oscillating electric field in the thin plasma layer between the vacuum and the target.