Nonlinear effects at the upper-hybrid layer

It is well-known that an extraordinary wave propagating along the density gradient mode converts into an electron Bernstein wave at the upper-hybrid layer. This paper reports various kinds of nonlinear effects associated with the electrostatic waves. Specifically, numerous possibilities of the three-wave decay interaction and the process of modulational instabilities are considered. The growth rate and threshold are obtained analytically. A comparative study of the growth rates and thresholds is carried out so as to emphasize the importance of slow plasma response. Also investigated were the effects of the pump profile, and the plasma nonuniformities on the temporal increment. Application of this work to tokamak devices, laboratory plasmas, as well as space plasmas, is discussed.