Solar Flare Effects in the F Region of the Ionosphere


ELEVEN years ago, Dieminger reported that the large solar flare of November 19, 1949, had a marked effect on the F region over Lindau, Germany1. A similar F-region effect was observed at Okinawa and probably at Singapore at the time of the outstanding flare of February 23, 19562,3. In addition to being very large, these flares were notable in that they were two of the five flares that had occurred up to that time during which increases in sea-level cosmic ray had been observed. Yet, because the F-region effect had been detected at so few of the sunlit ionospheric sounding stations, some doubt remained as to the correct interpretation of these observations.

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  1. 1

    Dieminger, W., and Geisweid, K. H., J. Atmos. Terr. Phys., 1, 42 (1950).

  2. 2

    Shapley, A. H., and Knecht, R. W., Inst. Rad. Eng. Trans. AP., 5, 326 (1957).

  3. 3

    Minnis, C. M., and Bazzard, G. H., Nature, 181, 690 (1958).

  4. 4

    Watts, J. M., and Davies, K., J. Geophys. Res., 65, 2295 (1960).

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KNECHT, R., DAVIES, K. Solar Flare Effects in the F Region of the Ionosphere. Nature 190, 797–798 (1961).

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