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Nonlinear dynamics of high-intensive femtosecond laser pulses in plasmas

Recent progress in powerful subpicosecond laser generation technology has stimulated interest in interaction of ultrashort electromagnetic pulses with nonlinear media. Being a classical example of a nonlinear medium and a traditional object of laboratory investigations, the plasma demonstrates an extreme variety in behavior under the action of the electromagnetic fields. Characteristic rise and relaxation times of nonlinear response can be varied by a few orders of magnitude depending on particle concentration, wavelength, external magnetic field, etc. Thus, the ultrashort pulse duration should be defined as a particular notion with respect to the phenomenon in question. In this paper we take interest in electromagnetic wave-plasma interaction processes faster than the relaxation of the nonlinear plasma response. In this context, we treat the interaction as essentially dynamical and the plasma as a medium with long-term memory properties. The nonsteady state of the nonlinear coupling and the plasma wake generation are two main features essential to the basic physical effects and applications.