Simultaneous SMM flat-crystal spectrometer and Very Large Array observations of solar-active regions

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6465303

Lang, K R; Willson, R F; Smith, K L; Strong, K T

High-resolution images of the quiescent emission from two solar-active regions are compared at 20-cm (VLA) and soft-x-ray (SMM-FCS) wavelengths. There are regions where the x-ray coronal loops have been completely imaged at 20-cm wavelength. In other regions, the x-ray radiation was detected without detectable 20-cm radiation, and vice versa. The x-ray data were used to infer average electron temperatures Te of about 3,000000 K and average electron densities of about 2.5 x 10/sup 9//cm/sup 3/ for the x-ray-emitting plasma in the two active regions. The thermal bremsstrahlung of the x-ray-emitting plasma is probably optically thin at 20-cm wavelength. Although the 20-cm brightness temperatures TB were always less than Te, suggesting optically thin layers, the thermal gyroresonance radiation from the x-ray-emitting plasma ought to be optically thick at 20-cm wavelength. The low TB can be explained if a higher, cooler plasma covers the hotter x-ray-emitting plasma. Thermal gyroresonance radiation must account for the intense 20-cm radiation near and above sunspots where no x-ray radiation is detected. The potential of 20-cm (VLA) and soft x-ray (SMM-FCS) comparisons is discussed.

• Research Organization: Tufts Univ., Medford, MA (USA). Dept. of Physics and Astronomy
• OSTI ID: 6465303
• Report Number(s): AD-A-179698/6/XAB
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
ELECTRON TEMPERATURE
EMISSION
IMAGES
IONIZING RADIATIONS
RADIATIONS
RADIOWAVE RADIATION
SHORT WAVE RADIATION
SOFT X RADIATION
SOLAR ACTIVITY
STARSPOTS
STELLAR ACTIVITY
SUNSPOTS
X RADIATION