Accession Number:

ADA179664

Title:

J. VLA (Very Large Array) of a Solar Noise Storm,

Descriptive Note:

Corporate Author:

TUFTS UNIV MEDFORD MA DEPT OF PHYSICS

Personal Author(s):

Report Date:

1986-01-01

Pagination or Media Count:

20.0

Abstract:

The first Very Large 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 kms. 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 Earths 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.

Subject Categories:

  • Astrophysics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE