Accession Number : AD0704552

Title :   SOLAR OBSERVATIONS AT 8.6-mm WAVELENGTH.

Descriptive Note : Physical sciences research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Kalaghan,Paul M. ; Telford,Larry E.

Report Date : JAN 1970

Pagination or Media Count : 52

Abstract : The advent of manned space flights has focused attention on the biological threat posed by solar proton flares. In an effort to close one of the gaps in the observation of the solar spectrum, AFCRL has initiated a high resolution millimeter wavelength solar observation program. This report covers the observational approach and initial findings of this program based upon observations from May to December 1968. The equipment and procedures used to produce spectroheliograms at 8.6 mm, using the AFCRL 29-ft Millimeter Wave Antenna, are described. The quiet sun at 8.6 mm appeared to have a brightness temperature of 8400 plus or minus 600 K blackbody and a 'radio diameter' 3 percent greater than the optical disk. The presence of active regions during this period was characterized by localized enhanced regions exhibiting temperature increases from 1 to 28 percent of the quiet sun level. The enhancement and the positions of these regions have been compared with 9.1-cm radio data and various other optical data. The locations of the 8.6-mm enhanced regions are contained within calcium plages. All proton events observed originated only in highly enhanced (Class III) regions. Further observations are in progress to increase the sample size of observed proton events to further refine the possibility of prediction of these events. (Author)

Descriptors :   (*SOLAR FLARES, PREDICTIONS), (*SOLAR RADIATION, *MILLIMETER WAVES), EXTRATERRESTRIAL RADIO WAVES, PROTONS, SOLAR ATMOSPHERE, RADIOFREQUENCY SPECTROSCOPY, SUNSPOTS, BRIGHTNESS

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE