Nonlinear kinetic Alfven waves in space plasmas with generalized (r,q) distribution

In this paper, we have investigated linear and nonlinear propagation of kinetic Alfven waves in which the electrons have been assumed to follow generalized ( r , q ) distribution. We have shown that ( r , q ) distribution gives us most of the distributions observed in space plasmas. We have varied the flatness parameter r and the tail parameter q to explore the linear and nonlinear propagation characteristics of kinetic Alfven waves. We have also discussed the limiting cases. It has been shown that our results agree well with Fast and Freja observations of the nonlinear kinetic Alfven waves. An important feature of our study is the formation of rarefactive solitary structures. It has been shown that this result cannot be obtained with Maxwellian distribution and that it agrees well with the observations of Fast and Freja satellites.