  The behavior of isothermal plasma waves has been analyzed near the
Schwarzschild horizon. We consider a non-rotating background with
non-magnetized and magnetized plasmas. The general relativistic
magnetohydrodynamical equations for the Schwarzschild planar analogue spacetime
with an isothermal state of the plasma are formulated. The perturbed form of
these equations is linearized and Fourier analyzed by introducing simple
harmonic waves. The determinant of these equations in each case leads to a
complex dispersion relation, which gives complex values of the wave number.
This has been used to discuss the nature of the waves and their characteristics
near the horizon.
