Solar wind driven electrostatic instabilities with generalized r,q distribution function

Using Boltzmann Vlasov kinetic model with the flat-top non-Maxwellian distributed electrons and ions, a velocity power law energetic tail, known as the generalized r, q distribution, a current-less electrostatic instability namely ion acoustic which is driven by a stream of solar wind plasma is studied here. The instability threshold is affected and depends upon the spectral indices r and q. It is found that the growth rate increases with the decrease of spectral index. Moreover, such kinetic instability has also been discussed for a three species electron-ion-dust plasma using the generalized r, q distribution function. Such case is of interest when the solar wind is streaming through the cometary plasma in the presence of interstellar dust and excites electrostatic instabilities. In the limits of phase velocity of the waves larger and smaller than the thermal velocity of dust particles, the dispersion properties and growth rate of dust-acoustic mode are calculated analytically and has been plotted for different values of the spectral indices.