  We describe a new wave mode similar to the acoustic wave in which both
density and velocity fluctuate. Unlike the acoustic wave in which the
underlying distribution is Maxwellian, this new wave mode occurs when the
underlying distribution is a suprathermal kappa function and involves
fluctuations in the power law index, kappa. This wave mode always propagates
faster than the acoustic wave with an equivalent effective temperature and
becomes the acoustic wave in the Maxwellian limit as kappa goes to infinity.
