FLOWS AND DYNAMICS IN THE CORONA OBSERVED WITH THE CORONAL DIAGNOSTICSPECTROMETER (CDS)

EUV spectra obtained with the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) show significant hows o f plasma in active region loops, both at coronal and transition region temperatures. Wavelength shifts in the coronal lints Mg IX 368 Angstr om and Mg X 624 Angstrom corresponding to upflows in the plasma reachi ng velocities of 50 km s(-1) have been observed in an active region. S maller velocities are detected in the coronal lines Fe XVI 360 Angstro m and Si XII 520 Angstrom. Flows reaching 100 km s(-1) are observed in spectral lines formed at transition region temperatures, i.e., O V 62 9 Angstrom and O III 599 Angstrom, demonstrating that both the transit ion region and the corona are clearly dynamic in nature. Some high vel ocity events show even higher velocities with line profiles correspond ing to a velocity dispersion of 300-400 km s(-1). Even in the quiet Su n there are velocity fluctuations of 20 km s(-1) in transition region lines. Velocities of the magnitude presented in this paper have never previously been observed in coronal lines except in explosive events a nd flares. Thus, the preliminary results from the CDS spectrometer pro mise to put constraints on existing models of the flows and energy bal ance in the solar atmosphere. The present results an compared to previ ous attempts to observe flows in the corona.