  We study theoretically the mode conversion and the resonant absorption of
high frequency electromagnetic waves into longitudinal modes in magnetized and
stratified plasmas in the case where the external magnetic field is
perpendicular to both the directions of inhomogeneity and wave propagation.
Mode conversion is shown to occur only when the waves are extraordinary waves.
We develop an efficient method for calculating the mode conversion coefficient
for arbitrary spatial configurations of the plasma density and the external
magnetic field in a numerically exact manner using the invariant imbedding
method. We calculate the mode conversion coefficient extensively as a function
of the incident angle, the external magnetic field, and the plasma density in
the incident region. We show that there is strong asymmetry under the sign
change of the incident angle and the external magnetic field and find that the
mode conversion coefficient is close to one in certain ranges of the parameter
values. We discuss the implications of our results in plasma heating phenomena.
