Transformation of a nonlinear plasma wave into electromagnetic radiation in a periodic magnetic field

We study transformation of a nonlinear plasma wave into electromagnetic radiation in the periodic static magnetic field of an undulator. Such a wave can be excited by a short laser pulse or a relativistic electron bunch. The features of relativistic upper-hybrid plasma oscillations are analyzed. In the approximation of constant pump, resonance conditions of excitation of an electromagnetic wave and the characteristic transformation length are found. The nonlinear stage of transformation with allowance for pump depletion is considered. The studied phenomenon can be used for development of a high-power terahertz-radiatoin source. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 6, pp. 496–507, June 2007.