  Space plasmas are known to be out of (local) thermodynamic equilibrium, as
observations show direct or indirect evidences of non-thermal velocity
distributions of plasma particles. Prominent are the anisotropies relative to
the magnetic field, anisotropic temperatures, field-aligned beams or drifting
populations, but also, the suprathermal populations enhancing the high-energy
tails of the observed distributions. Drifting bi-Kappa distribution functions
can provide a good representation of these features and enable for a kinetic
fundamental description of the dispersion and stability of these collision-poor
plasmas, where particle-particle collisions are rare but wave-particle
interactions appears to play a dominant role in the dynamic. In the present
paper we derive the full set of components of the dispersion tensor for
magnetized plasma populations modeled by drifting bi-Kappa distributions. A new
solver called DIS-K (DIspersion Solver for Kappa plasmas) is proposed to solve
numerically the dispersion relations of high complexity. The solver is
validated by comparing to the damped and unstable wave solutions obtained with
other codes, operating in the limits of drifting Maxwellian and non-drifting
Kappa models. These new theoretical tools enable more realistic
characterizations, both analytical and numerical, of wave fluctuations and
instabilities in complex kinetic configurations measured in-situ in space
plasmas.
