COMPARISON BETWEEN COOL AND HOT PLASMA BEHAVIORS OF SURGES

Ground-based coordinated observations with the Multichannel Subtractiv e Double Pass spectrograph (MSDP) allowed us to obtain chromospheric i ntensity and velocity field maps below coronal structures during the l aunch of the NIXT payload on 1991 July 11 (eclipse day). A large Halph a ejection in AR 6713 (N38 W40) was detected during the NIXT flight. H owever, only a low level of X-ray emission was associated with this ev ent. In contrast, bright X-ray emission associated with a subflare was observed in a nearby active region, but with only a weak associated e jection in Halpha. A discussion of both of these events gives strong c onstraints on the triggering mechanisms of surges.