Nonlinear Sum and Difference Frequency Generation in an Inhomogeneous Plasma

An analytical study is made of the nonlinear generation of the sum and difference frequency components in the current density in a plasma due to two alternating electric fields, an electron density gradient and a tempreature gradient. The results of this study have been used in investigating the nonlinear growth of sum and difference frequency waves in a plasma when two electromagnetic waves of different frequencies are propagating along the same direction in it and, also, the magnitude of these frequency components in the reflected wave from a plasma free space interface when the two electromagnetic waves are incident normally on the interface.