Figure 3.

Results of independent fast and slow wave propagations when the velocity of the fast wave is varied. The velocity of the fast wave increases from the left column to the right column. The top panels display the resultant mixed rf wave forms, and the center and bottom panels show the corresponding dispersion curves and attenuation coefficients obtained when the mixed wave form is analyzed as if it contained only one wave. When v_fast is only 50 m∕s greater than v_slow (far left panels), the mixed wave form exhibits positive dispersion and a nearly linear attenuation coefficient. As v_fast becomes increasingly greater than v_slow (middle panels), the dispersion becomes negative. When v_fast is significantly larger than v_slow (far right panels), the dispersion curve and attenuation coefficient have complicated frequency-dependent behavior.