Response of the Corona to Magnetic Activity in Underlying Plage Regions

Abstract

We study the response of the solar corona to magnetic activity in the underlying plage regions using high-resolution Michelson Doppler Imager magnetograms co-aligned with multiwavelength images taken by TRACE at chromospheric and coronal temperatures. We show that the EUV emission above plage regions that are dominated by single-polarity magnetic elements always has an amorphous shape that topologically mimics the shape of the underlying plage. Spacetime slices of the amorphous emission in the coronal lines show coherent braidlike structures with almost constant period for a given area. Contrary to this, coronal emission above mixed-polarity plages is highly discrete and consists of sporadic localized radiative transients. As different regions of strongly inhomogeneous corona evolve in different ways, separate mechanisms for energy production, flow, and release are probably required. We argue that in all cases the primary energy source lies in continuous hydromagnetic activity among the photospheric magnetic fields. The character of this activity determines the processes of the extraction of energy and its transport throughout the solar atmosphere. We propose a physical mechanism that may explain the diverse properties of the UV/EUV emission in upper layers of atmosphere and its relevance to the photospheric magnetic fields.