UVCS/SOHO capability for determining coronal conditions before, during, and after CME's

The ultraviolet coronal spectrometer (UVCS)/SOHO instrument will provide spectroscopic determinations of plasma parameters describing the evolution of coronal conditions at the site of coronal mass ejections (CME's). Prior to a CME event, UVCS can provide an empirical model of the coronal region where the event originates. The model would include values for the proton density, temperature, and outflow velocity; the electron density and temperature; and minor ion densities, temperatures, and outflow velocities. This information would be determined for heliocentric heights from about 1.5 to 3.5 of the solar radius with a subset of the parameters determined up to heights of 12 of the solar radius. During the event, UVCS would repeatedly sample one or more heights between 1.5 and 3.5 of the solar radius with a time resolution of about 1 min. The goal would be to determine the mass and energy content of the CME as it moves outward. After the event, the conditions in the region would be determined as before. Information about the instrument optical specifications and sensitivity is provided.