HE-I 1083 NM OSCILLATIONS AND DOWNFLOWS NEAR THE NORTH SOLAR POLE

Imaging spectroscopic data of the Si I 1082.7 nm (photospheric) and He r 1083.0 nm (chromospheric) spectral lines were taken starting 22:05 U T on 23 July, 1996 with the NASA/NSO Spectromagnetograph at the NSO/Ki tt Peak Vacuum Telescope. Observations were made near the north solar pole, with a field of view of 100 by 400 are sec and with a temporal c adence of 53 s for 2 hr. Simple fitting to the line profiles measured the line position, depth, and spectral full-width at half-maximum. Pow er spectra of the velocity oscillations in each line were computed, an d the oscillation power in the 2 to 6 mHz frequency band versus view a ngle was measured to search for horizontal oscillations. Horizontal wa ves are not detected to limiting amplitudes (1 sigma) of 22 m s(-1) in the chromosphere and 9 m s(-1) in the photosphere. These values are u sed to estimate limits for the energy flux into the corona. The amplit ude of radial oscillations in the chromosphere is twice that of the ph otosphere. No statistically meaningful oscillation power is measured i n the spectral parameters of the He I line in the emission shell seen above the continuum limb. Finally, rapidly evolving red-shift events a re observed in the Her 1083 nm line on the disk; these events are some sort of coronal rain, and there are about 40 of these events on the s olar disk at any moment.