First Results on Quiet and Magnetic Granulation from SOUP. (Reannouncement with New Availability Information).

摘要

The flight of SOUP on spacelab 2 allowed the collection of time sequences of diffraction limited (0.5 arc second) granulation images with excellent pointing (0.003 arc seconds) and completely free of the distortion that plagues groundbased images. The p-mode oscillations are clearly seen in the data. Using fourier transforms in the temporal and spatial domain we have shown that the p-modes dominate the autocorrelation lifetime in magnetic regions. When these oscillations are removed the autocorrelation lifetime is found to be 500 seconds in quiet and 950 seconds in magnetic regions. In quiet areas exploding granules are seen to be common. It is hard to find a granule that does not explode or is not affected by an explosion. We speculate that a significant fraction of granule lifetimes are terminated by nearby explosions. Using local correlation tracking techniques we have been able to measure horizontal displacements, and thus transverse velocities, in the intensity field. In quiet sun it is possible to detect both super-and mesogranulation. Horizontal velocities are as great as 1000 m/s and the average velocity is 400 m/s. In magnetic regions horizontal velocities are much less, about 100 m/s.