Anomalous absorption of high power microwave pulse in a plasma filled waveguide

A high power short pulse microwave, propagating through a plasma filled waveguide, undergoes anomalous absorption by transferring ponderomotive energy to electrons. The electrons, under the ponderomotive force, move radially outward from the axial region on the timescale of plasma period 2π/ωp, taking away ponderomotive energy from the pulse. Part of that energy is stored in the space charge field of the ion channel thus created. The fractional energy lost by the pulse is significant for the pulse duration of the order of plasma period at higher plasma density (ωp≤ω/2) and electron quiver velocity (∼0.1 c) as observed experimentally by Cao et al. [Phys. Plasmas 28, 062307 (2021)].