DISAPPEARANCE OF TWO-PLASMON DECAY INSTABILITY IN PLASMAS PRODUCED BY ULTRASHORT LASER PULSES

Harmonic emission was studied from a plasma produced by ultrashort laser pulses. Unlike the harmonics from plasmas created by long (ns) laser pulses, the 3/2 harmonic emission was not observed in the interaction between plasmas and ultrashort laser pulses. A simple model is proposed to explain this phenomenon.