Accession Number : ADA113084

Title :   Interferometric Microwave Polarimetry as a Tool for Short-Term Solar Flare Prediction.

Descriptive Note : Rept. for 19 Feb 80-31 Mar 81,

Corporate Author : CALIFORNIA INST OF TECH PASADENA

Personal Author(s) : Hurford,G J

PDF Url : ADA113084

Report Date : Aug 1981

Pagination or Media Count : 29

Abstract : The purpose of this study is to look at a data base of interferometric solar microwave data in order to identify, evaluate and interpret preflare microwave signatures, with reference to their possible role in the short-term prediction of solar flares. Reserving the second half of this data base for verification of tentative results, 27 major flares were selected using optical, soft x-ray OR microwave flux criteria for which good quality interferometric data was available. These events were analysed in detail and very similar preflare signatures noted in four (15%) of the cases. The most common signature was a step-like increase in signal amplitude, accompanied by a decrease or reversal in the degree of polarization. Such a signature occurred between a few minutes to a few tens of minutes before the start of the impulsive phase. Optical data, available in three cases, showed the microwave changes were simultaneous with either small brightenings or small-scale filament disruptions. Preliminary results show that such microwave behavior occurs far too seldom for such an association with major flares to be a chance occurrence.

Descriptors :   *SOLAR FLARES, *PREDICTIONS, POLARIMETRY, SOLAR OBSERVATORIES, MICROWAVE INTERFEROMETRY, SIGNATURES, FORECASTING, COMPARISON, SOFT X RAYS, FAR ULTRAVIOLET RADIATION, SPACE STATIONS

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE