Spatially-Resolved Diagnostics of Coronal Heating in Solar Active Regions
Abstract
We study the relationship between EUV spectral line intensities and the photospheric magnetic field in solar active regions, using magnetograms from SOHO-MDI and EUV spectra of the Fe XVI 360.8 Å line ( K) and the O V 629.7 A line (220,000 K) from the Coronal Diagnostic Spectrometer on SOHO, recorded for several active regions. Two complementary analysis methods are compared - a global analysis applied to the coronal line emission (Fe XVI), and a spatially-resolved analysis of the transition region emission (O V). We overlay and compare spatial patterns of the O V emission and the magnetic flux concentrations, with a spatial resolution, and search for a relationship between the local O V line intensity and the photospheric magnetic flux density in each active region. While this dependence exhibits a certain amount of scatter, it can be represented by a power law fit. The average power index from all regions is . Applying static loop models, we derive the dependence of the volumetric heating rate on the magnetic flux density, , and compare it to the dependence predicted by the coronal heating models.
- Publication:
-
SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE
- Pub Date:
- January 2004
- Bibcode:
- 2004ESASP.547..341F
- Keywords:
-
- EUV emission;
- active regions;
- magnetic field;
- coronal heating