Flows and dynamics in the corona observed with the coronal diagnostic spectrometer (CDS)

EUV spectra obtained with the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) show significant hows of plasma in active region loops, both at coronal and transition region temperatures. Wavelength shifts in the coronal lints Mg IX 368 Angstrom and Mg X 624 Angstrom corresponding to upflows in the plasma reaching velocities of 50 km s(-1) have been observed in an active region. Smaller velocities are detected in the coronal lines Fe XVI 360 Angstrom 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 629 Angstrom and O III 599 Angstrom, demonstrating that both the transition region and the corona are clearly dynamic in nature. Some high velocity events show even higher velocities with line profiles corresponding to a velocity dispersion of 300-400 km s(-1). Even in the quiet Sun 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 and flares. Thus, the preliminary results from the CDS spectrometer promise to put constraints on existing models of the flows and energy balance in the solar atmosphere. The present results an compared to previous attempts to observe flows in the corona.