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Title: VLA (Very Large Array) observations of a solar-noise storm

Abstract

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 amore » 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.« less

Authors:
;
Publication Date:
Research Org.:
Tufts Univ., Medford, MA (USA). Dept. of Physics and Astronomy
OSTI Identifier:
6349173
Report Number(s):
AD-A-179664/8/XAB
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, 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

Citation Formats

Lang, K R, and Willson, R F. VLA (Very Large Array) observations of a solar-noise storm. United States: N. p., 1986. Web.
Lang, K R, & Willson, R F. VLA (Very Large Array) observations of a solar-noise storm. United States.
Lang, K R, and Willson, R F. 1986. "VLA (Very Large Array) observations of a solar-noise storm". United States.
@article{osti_6349173,
title = {VLA (Very Large Array) observations of a solar-noise storm},
author = {Lang, K R and Willson, R F},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/6349173}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}

Technical Report:
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