The Role of Magnetic Topology in the Heating of Active Region Coronal Loops

Abstract

We investigate the evolution of coronal loop emission in the context of the coronal magnetic field topology. New modeling techniques allow us to investigate the magnetic field structure and energy release in active regions. Using these models and high resolution multi-wavelength coronal observations from the Transition Region and Coronal Explorer (TRACE) and the X-ray Telescope (XRT) on Hinode, we are able to establish a relationship between the light curves of coronal loops and their associated magnetic topologies for NOAA Active Region 10963. We examine loops that show both transient and steady emission, and we find that loops that show many transient brightenings are located in domains associated with a high number of separators. This topology provides an environment for continual impulsive heating events through magnetic reconnection at the separators. A loop with relatively constant X-ray and EUV emission, on the other hand, is located in domains that are not associated with separators. This result implies that larger-scale magnetic field reconnections are not involved in heating plasma in these regions, and the heating in these loops must come from another mechanism, such as small-scale reconnections (i.e., nanoflares) or wave heating. Additionally, we find that loops that undergo repeated transient brightenings are associated with separators that have enhanced free energy. In contrast, we find one case of an isolated transient brightening that seems to be associated with separators with a smaller free energy.

36 pages, 11 figures, To appear in Astrophysical Journal

References in corpus (12)

• On Solving the Coronal Heating Problem
• Active region transition region loop populations and their relationship to the corona
• The role of torsional Alfven waves in coronal heating
• Evidence for Steady Heating: Observations of an Active Region Core with Hinode and TRACE
• Hydrostatic Modeling of the Integrated Soft X-Ray and EUV Emission in Solar Active Regions
• Hinode Calibration for Precise Image Co-alignment between SOT and XRT (November 2006 -- April 2007)
• Observation and Modeling of Coronal "Moss" With the EUV Imaging Spectrometer on Hinode
• Observations of Transient Active Region Heating with Hinode
• Modeling Evolving Coronal Loops with Observations from STEREO, Hinode, and TRACE
• Coronal Loop Expansion Properties Explained Using Separators
• Effects of partitioning and extrapolation on the connectivity of potential magnetic fields
• Deconstructing active region AR10961 using STEREO, Hinode, TRACE & SOHO

Cited by in corpus (4)

• Constraints on the Heating of High Temperature Active Region Loops: Observations from Hinode and SDO
• High-Lundquist Number Scaling in Three-Dimensional Simulations of Parker's Model of Coronal Heating
• The Relationship between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High Resolution Hinode Observations
• Evidence of the Relationship between the Emerging Magnetic Fields, Electric Currents, and Solar Flares Observed on May 10, 2012