Increase of electromagnetic radiation frequency in interaction with nonlinear plasma waves

Interaction of electromagnetic radiation with nonlinear plasma waves (NPW) was studied. It is shown that the noticeable reflection is realized on sharp electron concentration jumps in reversing NPW, for which electron maximum velocity is equal to or greater than the phase velocity of relativistic plasma waves. The interaction with one of jumps is considered. When NPW are excited by a short pulse of high-power laser radiation with carrier frequency ω₀ > ω ₁ ≫ ω_p (where ω₁ is the incident wave frequency and ω_p is the Langmuir frequency), the reflected wave intensity increases approximately as the ratio (ω₀÷ω₁)^8÷3. The conclusion is made that the frequency increase can be accompanied by sufficiently efficient energy conversion.