Co-Temporal Evolution of Magnetic Sources of Coronal and Chromospheric/Photospheric Irradiance Variability
Magnetic features emergent from the Sun's convection zone modulate the global radiative output throughout the solar atmosphere. Space-based radiometric monitoring by instruments onboard Yohkoh and UARS have tracked the decline in coronal soft X-rays concurrent with chromospheric and photospheric UV global fluxes from high activity in 1991 to the present solar minimum. Although these different global emissions can at times vary in quite different ways they each exhibit components of variability traceable to common magnetic variability sources, primarily sunspots, bright plages and active network. Comparisons of the SXT soft X-ray images of the corona with groundbased Ca K images of the chromosphere/ photosphere permit the establishment of relationships between these common magnetic sources in solar atmosphere regimes with quite different temperatures and densities. While the impact of large active regions seen in both the coronal and chromospheric images provides the dominant modulation of the emissions (although with different spectral signatures traceable to different spatial scales), more diffuse, extended magnetic sources also contribute to solar cycle changes in the overall background global emission of the corona as well as the chromosphere/photosphere.
AAS/Solar Physics Division Meeting #28
- Pub Date:
- May 1997