  The dispersion equation of MGD plasma waves measured in a reference frame
with a relative speed from that where they are generated is derived. The
analysis leads further from what is known for waves produced in stationary
plasmas in the presence of an imposed magnetic field, and includes terms
containing space gradients in the density and speed values in the continuity
and momentum equations of the plasma. The dispersion equation that is derived
leads to an Alfven wave and magnetogasdynamics wave modes whose distribution
with respect the direction of the imposed magnetic field varies with the
relative speed of the reference frame. For the particular case in which the
speed of the reference frame is zero the dispersion equation of the
magnetogasdynamic waves reduces to what is known for stationary plasmas. More
complicated waves with different distribution modes with respect to the
magnetic field direction are implied from the more general four-order
dispersion equation that is derived. A particular case is presented for a
non-zero speed value of the reference frame, but the derivation and analysis of
the corresponding solutions will be discussed in a forthcoming report.
