Electrostatic Bernstein waves in plasmas whose electrons have a dual kappa distribution: Applications to the Saturnian magnetosphere

The dispersion relation for Bernstein mode waves in a plasma having a kappa distribution as the equilibrium velocity distribution for both hot and cool electron components is derived without the use of infinite sums of Bessel functions. In contrast to the single electron component case, points where the perpendicular group velocity vanishes, i.e., partial derivative omega/partial derivative k(perpendicular to) = 0 are found below the upper hybrid band. In the single electron species case only one such maximum/minimum is found in and above the upper hybrid band. However, in the case of two electron species, an additional maximum/minimum is observed. Our model is applied to conditions observed in the Saturnian magnetosphere where the emergence of these points may have important consequences for the interpretation of the observed microstructure.