  The paper, authored by J. A. S. Lima et al, was published in Phys. Rev. E in
2000 has discussed the dispersion relation and Landau damping of Langmuir wave
in the context of the nonextensive statistics proposed by Tsallis. It has been
cited by many authors because the dispersion relation in Tsallis formalism
present a good fit to the experimental data when q<1, while the classical
result based on Maxwellian distribution only provides a crude description.
However, the results obtained in this paper are problematic. In this comments
on the paper we shall derive the correct analytic formulas both for the
dispersion relation and Landau damping in Tsallis formalism. We hope that this
comments will be useful in providing the correct results.
