Evolution of two EIT/H alpha Moreton waves

Since the discovery of EIT waves, questions have remained about the driver of these disturbances and their association with the chromospheric Moreton waves. In order to resolve some of these issues, two flare-associated trans ient events (1997 November 3 and 1998 May 2) observed simultaneously in H a lpha and EIT are analyzed. The cospatiality of Moreton and EIT wave fronts is established, and a deceleration of the disturbances is found in both eve nts. In the case of 1998 May 2, a detailed analysis of the evolution of the Moreton wave, its kinematics, and perturbation profile is carried out. The results-deceleration, broadening, and decrease of intensity of the profile s-favor the fast-mode shock ("blast wave") scenario over the coronal mass e jection-associated magnetic field evolution hypothesis.