Relativistic cross-focusing of two chirped laser pulses in thermal quantum plasma

Relativistic cross-focusing of two chirped pulse lasers in thermal quantum plasma has been analyzed. Two chirped laser pulses are propagating in thermal quantum plasma under relativistic nonlinearity which induces the cross-focusing of lasers. A linear frequency chirp is considered which plays an important role in minimizing the laser beam width parameter, and hence, the cross-focusing becomes stronger and occurs earlier. The equations of beam width parameters of the lasers in thermal quantum plasma are derived by using WKB and paraxial ray approximations. It is observed that the beam width parameter decreases with the increase in the value of the chirp parameter. Moreover, it is seen that the cross-focusing becomes more robust for higher values of chirp parameter, plasma frequency, and laser intensity. Furthermore, it is realized that the cross-focusing effect is stronger in the thermal quantum plasma compared to the classical one. The result of this study may be useful in clarifying the mechanism of laser propagation in the fast ignition of ICF experiments, where quantum effects in deuterium-tritium plasma are dominant.