VLA (Very Large Array) observations of a solar-noise storm
The first Very Large Array (VLA) observations of the sun at 92-cm wavelength (328 MHz) are presented. A solar-noise storm, which lasted at least 3 hours, was detected at this wavelength; it consisted of burst-like spikes superimposed on a slowly varying background, and both storm components were 95 + or - 5% right-hand circularly polarized. A long-duration soft-x-ray event preceded the radio radiation by 30 m, suggesting a disturbance moving outwards at a velocity of v = 78 km/s. The 92-cm noise storm was resolved with an angular resolution of 9 sec for time intervals as short as 13 s. During the onset and early phases, the storm consisted of four compact sources, each with an angular diameter of 40 sec, oriented within an elongated source with angular dimensions of 40 sec by 200 sec. During the subsequent hour, the most-intense emission was located in two 40-sec sources separated by 100 sec. Snapshot maps revealed a persistent elongated source at successive peaks, with a scatter in the source position. A systematic position shift of Deta Theta/sub I/ > or = 15 sec can be produced by the Earth's ionosphere, but these effects can be removed by frequent observations of a nearby calibrator source. The observations confirm previously reported trends for a decrease in source size at higher frequencies, but they suggest a hitherto unresolved complexity in source structure.
- Research Organization:
- Tufts Univ., Medford, MA (USA). Dept. of Physics and Astronomy
- OSTI ID:
- 6349173
- Report Number(s):
- AD-A-179664/8/XAB
- Country of Publication:
- United States
- Language:
- English
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VLA observations of a solar noise storm
VLA (Very Large Array) observations of a solar-noise storm
Related Subjects
GENERAL PHYSICS
IONOSPHERE
MAGNETIC STORMS
SOLAR ACTIVITY
RADIO NOISE
SOFT X RADIATION
CALIBRATION
EMISSION
RADIO TELESCOPES
SUN
ANTENNAS
EARTH ATMOSPHERE
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
IONIZING RADIATIONS
MAIN SEQUENCE STARS
NOISE
PLANETARY IONOSPHERES
RADIATIONS
RADIO EQUIPMENT
RADIOWAVE RADIATION
STARS
TELESCOPES
X RADIATION
640104* - Astrophysics & Cosmology- Solar Phenomena
640201 - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena