Laser beat wave terahertz generation in a clustered plasma in an azimuthal magnetic field

Laser beat wave excitation of terahertz radiation in a rippled density clustered plasma, in the presence of an azimuthal magnetic field, is investigated. The lasers exert a beat ponderomotive force on cluster electrons, imparting them an oscillatory velocity with a significant transverse component due to the azimuthal magnetic field. The oscillatory velocity beats with the cluster density ripple and produces a nonlinear current, driving terahertz radiation. The terahertz field turns out to have ring shaped distribution. Its amplitude is enhanced by the cluster plasma resonance when 4 pi/3n(c0)r(c0)(3)n(e)/(omega(2) - omega(2)(pe)/3) > n(0)/omega(2). (C) 2011 American Institute of Physics. [doi:10.1063/1.3591361]