We studied the EUV line spectra of three flare observed with the NRL slit spectrograph on Skylab. The electron densities in the flare transition-zone plasmas are determined from density-sensitive lines of Sim and O IV. The electron densities in all three flares studied were greatest during the flare maximum with values of the order of 1012 cm -3. The density decreases by a factor of 2 to 3 in the decay phase of the flares. The intensities of EUV lines from the flare chromospheric and transition-zone plasmas all are greatly enhanced. In contrast to lines for O I, C I, Fe II and other chromospheric ions, the lines of O Iv and N v and other transition-zone lines are not only enhanced but also very much broadened.
Fitting of the N v 1242 ]k line with a two-gaussian model shows that for two of the flares studied, there is a red-shifted component in addition to an unshifted component. The shifted component in the N v line profiles is interpreted as due to a dynamic and moving plasma with a bulk motion velocity of 12 km s-1 for one flare and more than 70 km s -1 for the other. The broadened line profiles indicate that there are large turbulent mass motions with random velocities ranging from 30 to 80 km s -1. * Bail Corporation. Now with NASA/Marshall Space Flight Center.