A study of the magnetic and velocity fields in an active region.
Abstract
A time sequence of magnetograms and velocity-grams in the Hα and Fe I 6569 Å lines has been made at a rate of 12 h−1 of McMath Region 10385 from 26 to 29 October, 1969. The 14 flares observed during this period have been studied in relation to the configuration and changes in the magnetic and velocity fields. There was little correlation between flare position and the evolutionary changes in the photospheric magnetic and velocity field, except at large central meridian distances where the velocity observations suggested shearing taking place at flare locations. At central meridian distances > 30° we found that flares are located in areas of low line-of-sight photospheric velocity surrounded by higher velocity hills. The one exception to this was the only flare which produced a surge. Blue-shifted velocity changes in the photosphere of 0.3 to 1 km s−1 were observed in localized areas at the times of 8 of 14 flares studied.
- Publication:
-
Solar Physics
- Pub Date:
- March 1976
- DOI:
- 10.1007/BF00152261
- Bibcode:
- 1976SoPh...47..233H
- Keywords:
-
- Chromosphere;
- Flow Velocity;
- Photosphere;
- Solar Flares;
- Solar Magnetic Field;
- Astronomical Maps;
- H Alpha Line;
- Magnetic Field Configurations;
- Magnetic Signatures;
- Solar Spectra;
- Velocity Distribution;
- Solar Physics;
- Flare;
- Active Region;
- Velocity Field;
- High Velocity;
- Localize Area