Early evolution of an X-ray emitting solar active region.
Abstract
The birth and early evolution of a solar active region has been investigated using X-ray observations from the Lockheed Mapping X-Ray Heliometer on board the OSO-8 spacecraft. X-ray emission is observed within three hours of the first detection of Hα plage. At that time, a plasma temperature of 4 × 106 K in a region having a density of the order of 1010 cm−3 is inferred. During the fifty hours following birth almost continuous flares or flare-like X-ray bursts are superimposed on a monotonically increasing base level of X-ray emission produced by plasma with a temperature of the order 3 × 106 K. If we assume that the X-rays result from heating due to dissipation of current systems or magnetic field reconnection, we conclude that flare-like X-ray emission soon after active region birth implies that the magnetic field probably emerges in a stressed or complex configuration.
- Publication:
-
Solar Physics
- Pub Date:
- November 1977
- DOI:
- 10.1007/BF00150884
- Bibcode:
- 1977SoPh...55..181W
- Keywords:
-
- Magnetic Field Reconnection;
- Solar Activity;
- Solar Physics;
- Solar X-Rays;
- Oso-8;
- Plasma Radiation;
- Solar Flares;
- Spaceborne Astronomy;
- Solar Physics;
- Magnetic Field;
- Flare;
- Active Region;
- Early Evolution;
- Current System;
- Evolution:Solar Active Regions;
- Solar Active Regions:X Rays