On the analogy between a wave packet of quasi-monochromatic plasma waves and a particle in a gravitational field

In a cold collisionless plasma, the energy-mass relation for a wave packet propagating radially in the Schwarzschild gravitational field is derived. The dispersion equation of transverse waves in the plasma in the gravitational field is equivalent to the energy-mass relation. The quasi-particle description of the wave packet yields no new red-shift formula. (author)