Solar Radio Burst Measurements on 0.43-, 3.15-and 9.4-Cm Wavelengths.

Abstract

view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Solar Radio Burst Measurements on 0.43-, 3.15-and 9.4-Cm Wavelengths. Edelson, S. ; Grant, C. Abstract Analyses of a series of solar outbursts observed on 0.43-, 3.15- and 9.4-cm wavelengths between November 30, and December 3, 1959 at the U. S. Naval Research Laboratory, strongly suggests that the projected positions of all the radio sources were located in Ha flares occurring in the Mc Math plage region 5476. The active areas most closely associated with the radio sources were determined by correlating the Ha light curves with the radio flux curves. The average solar flux levels at the times just preceding each of the disturbances were (6800 *600) 10-~~, (248*12) 10-~~ and (234*8) 10-~~ w m-2 (c/s)-' on 0.43, 3.15, and 9.4 cm, respectively. The maximum total solar flux at the times of the disturbances ranged from ~ 14 000x 10-~~ to 6300 X1022on0.43cm, ~850x10-2 to 420X10-22 on 3.15 cm, and >1630x10-22 to 280x10-22 wm~2 (c/s)-' on 9.4 cm. A comparison of the average solar flux levels with the spectrum of the quiet sun extrapolated to 0.43 centimeters shows that there was no detectable increase in the thermal emission at 0.43 cm. Solar flux calculations at 0.43 cm, based on measurements made between April 29 and June 1, 1960, yielded a value of (6820*600) 10-~~ wm2 (c/s)-'. In order to detect a slowly varying component, at 0.43 cm, which may be considerably less than the uncertainty of *600 X 10-22 w uf2 (c/s) -1, systematic observations over a longer period may be necessary. Brightness temperatures of the radio-burst sources were deduced from the measured flux increase at each wavelength, and the assumed source size. Diameters of the radio sources of about I minute of arc were inferred from the discrete Ha correlating regions, and calculated on the assumption that they were radial projections above the optical area and were at heights of 20000 km at 0.43 cm, 30000 km at 3.15 cm, and 37000 km at 9.4 cm. The 3.15-a~ height was interpolated using the measured time differences between the peak flux at each of the wavelengths observed in the December 1 event. The following brightness temperatures thus deduced: 3.5 x107 to 1.8x108 at 0.43 cm, 6.0x108 to 1.8x109 at 3.15 cm, and 4.3x109 to 3.1x10'0 0K at 9.4 cm, suggest that this enhanced radiation is probably arising from nonthermal emission. Publication: The Astronomical Journal Pub Date: 1960 DOI: 10.1086/108088 Bibcode: 1960AJ.....65Q.488E full text sources ADS |