Effect of switching-off of a plasma medium on a traveling wave

Summary Form only given, as follows. It is known that a sudden creation of a plasma medium of plasma frequency omega /sub p/ splits a traveling wave of frequency omega /sub 0/ into two new waves of frequencies omega /sub 1.2/=+or-( omega /sub 0//sup 2/+ omega /sub p//sup 2/)/sup 1/2/. The negative value for the frequency indicates a reflected wave. The effect of a sudden collapse of the plasma medium on a traveling wave of frequency omega /sub 0/ has been shown by the author to be the creation of two new waves of frequencies omega /sub 1.2/=+or-( omega /sub 0//sup 2/- omega /sub p//sup 2/)/sup 1/2/. These are propagating waves only if omega /sub 0/> omega /sub p/. The power in the reflected wave has a maximum of 3.7% of the power in the incident wave. The variation in the frequencies of the new waves and power carried by them with the incident wave frequency is shown. A numerical solution has been obtained for the case of a gradual collapse of the plasma medium. For the case of a slow decay of the particle density, an approximate WKB-type solution has been obtained.<>