Steady flows in the chromosphere and transition-zone above active regions as observed by OSO-8 |
| |
Authors: | Bruce W Lites |
| |
Institution: | (1) Laboratory for Atmospheric and Space Physics, University of Colorado, 80309 Boulder, Colo., U.S.A. |
| |
Abstract: | Two years of data from the University of Colorado ultraviolet spectrometer aboard OSO-8 were searched for steady line-of-sight flows in the chromosphere and transition-zone above active regions. The most conspicuous pattern that emerges from this data set is that many sunspots show persistent blueshifts of transition-zone lines indicating velocities of about 20 km s–1 with respect to the surrounding plage areas. The data show much smaller shifts in ultraviolet emission lines arising from the chromosphere: the shifts are frequently to the blue, but sometimes redshifts do occur. Plage areas often show a redshift of the transition-zone lines relative to the surrounding quiet areas, and a strong gradient of the vertical component of the velocity is evident in many plages. One area of persistent blueshift was observed in the transition-zone above an active region filament. The energy requirement of these steady flows over sunspots is discussed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|