Physical properties of individual coronal loops in a solar active region observed in the XUV

Journal Article · Sun Jun 01 04:00:00 EDT 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158032· OSTI ID:5096964

Cheng, C

We studied the XUV observations of the active region McMath 12378 obtained with the NRL XUV spectroheliograph on Skylab. The XUV emission of the active region consists predominantly of loops which can be roughly divided into three distinctive structural groups according to their temperature of formation. The first group, observed in coronal ions such as Fe XV and Fe XVI, are mainly small and compact loops, which span directly across the photospheric magnetic neutral lines separating the two strong magnetic field regions with opposite polarity. The second group, with temperatures of 5 x 10/sup 5/ to 1 x 10/sup 6/ K, is typified by large Ne VII and Mg IX loops, which connect preferably the bipolar magnetic regions outside of the neutral line. The Ne VII loops are sharply defined while the Mg IX loops are more diffuse. The third group of emission structures is the chromospheric ribbons in He II, which are situated on each side of the magnetic neutral line. These He II ribbons are identified as the loci of the footpoints of the coronal Fe XV--XVI loops.

• Research Organization: NASA Marshall Space Flight Center, Marshall Space Flight Center, Alabama
• OSTI ID: 5096964
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 238:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED PARTICLES
ELECTROMAGNETIC RADIATION
EMISSION
EXTREME ULTRAVIOLET RADIATION
IONIZING RADIATIONS
IONS
IRON IONS
MAGNETIC FIELDS
PHYSICAL PROPERTIES
RADIATIONS
SOLAR ACTIVITY
SOLAR CORONA
SOLAR RADIATION
SPECTRA
STELLAR RADIATION
STRUCTURAL MODELS
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
X RADIATION
X-RAY SPECTRA