  Observations show that plasma particles in the solar wind frequently display
power-law velocity distributions, which can be isotropic or anisotropic.
Particularly, the velocity distribution functions of solar wind electrons are
frequently modeled as combination of a background Maxwellian distribution and a
non-thermal distribution which is known as the "halo" distribution. For fast
solar wind conditions, highly anisotropic field-aligned electrons, denominated
as the "strahl" distribution, are also present. Motivated by these
observations, the present paper considers a tenuous plasma with Maxwellian
ions, and electrons described by a summation of an isotropic Maxwellian
distribution and an isotropic Kappa distribution. The formalism of weak
turbulence theory is utilized in order to discuss the spectra of electrostatic
waves that must be present in such a plasma, satisfying conditions of
quasi-equilibrium between processes of spontaneous fluctuations and of induced
emission. The kappa index and relative density of the Kappa electron
distribution are varied. By taking into account effects due to electromagnetic
waves into the weak turbulence formalism, we investigate the electromagnetic
spectra that satisfy conditions of "turbulent equilibrium", and also the time
evolution of the wave spectra and of the electron distribution, which occurs in
the case of the presence of an electron beam in the electron distribution.
