Magnetoplasma Terahertz Solitons and Collapsing Pulses in Narrow-Gap Semiconductors

It is investigated theoretically a possibility of propagation of terahertz envelope solitons and collapsing pulses in narrow-gap semiconductors along a bias magnetic field. The quasi-relativistic electron nonlinearity is considered. The equivalence of the semi-classical kinetic approach and the hydrodynamic one is demonstrated. For low frequency helicon waves strict limitations for the realization of envelope solitons and collapsing pulses are pointed out. At higher frequencies the frequency intervals for envelope temporal and spatial soliton propagation and the wave collapse are determined. The bias magnetic field controls the nonlinear wave dynamics there.