Abstract
Radio emission from the sun at a wavelength of 9.1 cm has been studied during the quiet sun years, 1964–65, using the Stanford spectroheliograph. A map of the quiet sun has been prepared and compared with a map produced using the same instrument in 1960. On the basis of ray tracing results the differences in the two maps can be explained by a decrease in the electron density by a factor of 1.4 at the equator and 1.1 at the poles.
The slowly varying component of emission can be attributed to electron density enhancements by a factor of 2 to 5 over regions with dimension 2′ to 6′ arc. Changes of flux and width of these regions with longitude on the sun agree with the results of ray tracing using a very simple model for the regions. The detection of sunspot groups on the far side of the sun by measuring increased 9.1 cm emission at the limbs is shown to be possible.
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References
Allen, C. W.: 1947, Monthly Notices Roy. Astron. Soc. 107, 426.
Allen, C. W.: 1963, Astrophysical Quantities, 2nd ed., Athlone Press, London.
Bracewell, R. N. and Deuter, J.: 1966, private communication.
Bracewell, R. N. and Preston, G. W.: 1956, Astrophys. J. 123, 14.
Bracewell, R. N. and Swarup, G.: 1961, Trans. I.R.E. AP-9, 22.
Budden, K. G.: 1961, Radio Waves in the Ionosphere, Cambridge University Press, Cambridge, pp. 271–282.
Christiansen, W. N. and Warburton, J. A.: 1953, Australian J. Phys. 6, 262.
Cillié, G. G. and Menzel, D. H.: 1935, Harvard College Observatory Circular 410.
CRPL: U.S. Department of Commerce, N.B.S. Bulletin, Solar Geophysical Data, Part B, Boulder, Colo.
Jaeger, J. C. and Westfold, K. C.: 1949, Australian J. Sci. Res. A2, 322.
Kakinuma, T. and Swarup, G.: 1962, Astrophys. J. 136, 975.
Kundu, M. R.: 1965, Solar Radio Astronomy, Interscience, New York.
Newkirk, G.: 1961, Astrophys. J. 133, 982.
Pagel, B. E. J.: 1964, Ann. Rev. Astron. Astrophys. 2, 267.
Pawsey, J. L. and Bracewell, R. N.: 1955, Radio Astronomy, Clarendon Press, Oxford.
Pawsey, J. L. and Smerd, S. F.: 1953, in The Sun (ed. by G. P. Kuiper), University of Chicago Press, Chicago, p. 466.
Ratcliffe, J. A.: 1959, The Magneto Ionic Theory and its Application to the Ionosphere, Cambridge University Press, Cambridge.
Riddle, A. C.: 1969, Solar Phys. 6, 251.
Roosen, J. and Goh, T.: 1967, Solar Phys. 1, 242.
Scheuer, P. G.: 1960, Monthly Notices Roy. Astron. Soc. 120, 231.
Smerd, S. F.: 1950, Australian J. Sci. Res. A3, 34.
Smerd, S. F. and Westfold, K. C.: 1949, Phil. Mag. Ser. 7, 40, 831.
Solar Geophysical Data: Feb. 1968, Descriptive Text, U.S. Department of Commerce, Washington, D.C.
Sturrock, P. A.: 1964, Nature 203, 285.
Swarup, G.: 1961, Dissertation, Stanford University, Stanford, Calif.
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Riddle, A.C. The quiet and slowly varying components of 9.1 cm radio emission during the solar minimum. Sol Phys 7, 434–447 (1969). https://doi.org/10.1007/BF00146146
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DOI: https://doi.org/10.1007/BF00146146