Electron residual energy of optical-field-ionized plasmas driven by subpicosecond laser pulses

A model of the optical-field ionization (OFI) involving above-threshold ionization (ATI) and inverse brehmsstrahlung (IB) as the most important electron heating mechanisms, is used to compare recently reported experimental data with theoretical values of electron residual energy (temperature) in a laser plasma created by subpicosecond laser pulses. A 1D particle-in-cell (PIC) code is used to determine the effect (if any) on the residual energy due to space charge fields induced in plasma. Satisfactory agreement is found between most of the available experimental data for neutral gases and the results of the models. The strong influence of the laser pulse rise time on the electron temperature is noted.