First results on quiet and magnetic granulation from SOUP.
Abstract
The flight of Solar Optical Universal Polarimeter (SOUP) on Spacelab 2 allowed the collection of time sequences of diffraction limited (0.5 arc sec) granulation images with excellent pointing (0.003 arc sec) 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, it was 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 sec in quiet and 950 sec in magnetic regions. In quiet areas exploding granules are seen to be common. It is speculated that a significant fraction of granule lifetimes are terminated by nearby explosions. Using local correlation tracking techniques it was able to measure horizontal displacements, and thus transverse velocities, in the magnetic 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.
- Publication:
-
NASA Conference Publication
- Pub Date:
- September 1987
- Bibcode:
- 1987NASCP2483...55T
- Keywords:
-
- Solar Atmosphere;
- Solar Granulation;
- Solar Magnetic Field;
- Solar Oscillations;
- Astronomical Photography;
- Fourier Transformation;
- Magnetic Flux;
- Polarimetry;
- Sunspots;
- Solar Physics;
- Solar Granulation:Models;
- Solar Granulation:Solar Magnetic Regions;
- Solar Granulation:Solar Oscillations;
- Solar Magnetic Regions:Solar Granulation;
- Solar Oscillations:Solar Granulation