Radiation Amplification by Photoionized Inert Gas Plasma Layer in a Magnetic Field

The interaction of a circularly polarized electromagnetic wave with a layer of photoionized inert gas plasma in the magnetic field has been studied. A detailed analysis of the reflection and transmission coefficients of the wave under conditions where the wave frequency is the same as the photoelectron cyclotron frequency is given. The possibility of a strong increase in the reflection and transmission coefficients, when negative small absolute values of the imaginary part of the photoionized plasma dielectric permittivity are released, has been revealed. It is shown that in the photoionized plasma layer obtained in the process of fast multiphoton ionization of xenon atoms at atmospheric pressure, there is a possibility of increasing the field strength of terahertz radiation by more than two orders of magnitude.