High-resolution photography of the solar chromosphere. XIX - Flow velocities along an active region loop
Abstract
True flow velocities along the central axis of an active region loop have been determined for the first time. This has been done by combining measurement of the line-of-sight velocity at a number of points with a mathematical technique for reconstructing the true shape, size, and orientation of a (tilted) loop observed on the solar disk. The loop material is found to rise from the surface along one leg with an increasing upward velocity despite the retarding effect of gravity. Descending material in the other leg suffers a retarding force and does not attain the velocity of free fall. The derived velocities are supersonic at all points measured; the Mach number exceeds 5 at one location.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1984
- DOI:
- 10.1086/162317
- Bibcode:
- 1984ApJ...283..392L
- Keywords:
-
- Astronomical Photography;
- Chromosphere;
- Coronal Loops;
- Solar Prominences;
- Axial Flow;
- Coordinate Transformations;
- H Alpha Line;
- Plasma Acceleration;
- Solar Velocity;
- Velocity Measurement;
- Solar Physics