A semiempirical model of the upper flare chromosphere.

Ultraviolet spectra of the 1973 August 9 flare taken with the NRL S082B spectrograph aboard ATMSkylab have been analyzed to derive a seiempirical model of the flare chromosphere between 5500 and 10/sup 5/ K. The hydrogen radiative transfer is solved to obtain a self-consistent set of physical conditions within the flare atmosphere, from which lines profiles and continua of the ions C I, C II, C III, and C IV are synthesized and compared to the observations. The model exhibits a rapid rise in the temperature at a column mass of 3 x 10/sup -4/ g cm/sup -2/. There is some evidence for much of the C III line emission arising from flare kernels not exceeding 3'' in size, and the C IV line profiles indicate the possibility of nonequilibrium excitation.