Very large array observations of coronal loops at 20 centimeter wavelength

Journal Article · Thu Jul 01 04:00:00 EDT 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160087· OSTI ID:5031968

Lang, K R; Willson, R F; Rayrole, J

Looplike coronal structures have been observed in VLA synthesis maps at 20 cm wavelength with an angular resolution of 3.''7 x 5''. The 20 cm loops extend across regions of opposite magnetic polarity in the underlying photosphere. The absence of detectable circular polarization suggests that the 20 cm loops are optically thick with brightness temperatures equal to coronal electron temperatures of millions of degrees. We interpret the 20 cm emission in terms of the optically thick bremsstrahlung of thermal electrons trapped within magnetic loops which are in hydrostatic equilibrium. The 20 cm loops have temperature maxima in their central regions as is expected from hydrostatic loops, and they also satisfy the hydrostatic scaling relation. The semilength Lroughly-equal5 x 10/sup 9/ cm, maximum electron temperature T/sub e/(max)roughly-equal3 x 10/sup 6/ K, pressure p = 2 dyn cm/sup -2/, and electron density N/sub e/roughly-equal2.5 x 10/sup 9/ cm/sup -3/ of the 20 cm loops are all characteristic of the coronal loops detected at X-ray wavelengths. This discovery opens up the possibility of using 20 cm synthesis maps to investigate the detailed structure, evolution, and preflare activity of coronal loops.

• Research Organization: Department of Physics, Tufts University
• OSTI ID: 5031968
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 258:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
INTERFEROMETRY
LEPTONS
MAGNETIC FIELDS
PHOTOSPHERE
POLARIZATION
RADIATIONS
RADIOWAVE RADIATION
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR ELECTRONS
SOLAR PARTICLES
SOLAR RADIATION
SOLAR RADIOWAVE RADIATION
STELLAR RADIATION