Letter | Published:

Sudden Increase in the Ionosphere F2-Region Ionization associated with Solar Flares

Naturevolume 193pages462463 (1962) | Download Citation



Knecht and Davies1 reported recently two cases of sudden increase in the F2-layer ionization, associated with solar flares. With the previous communications of Dieminger2, Minnis and Bazzard3 and Harrison4 a total of five cases has been reported up to now. We present five more cases, observed at São Paulo during November 20, 1960, and July 11, 12, 18 and 21, 1961. We are ignoring here another event associated with the 3 + flare of July 23. On that day an ionospheric storm was in progress, causing very erratic behaviour of the F-layer.

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  1. 1

    Knecht, R. W., and Davies, K., Nature, 190, 797 (1961).

  2. 2

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

  3. 3

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

  4. 4

    Harrison, V. A. W., Nature, 186, 228 (1960).

  5. 5

    Ratcliffe, J. A., Physics of the Upper Atmosphere, 435 (Acad. Press, New York and London, 1960).

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  1. Depto. de Física, Escola Politécnica, Universidade de São Paulo.

    • L. Q. ORSINI
    •  & R. H. MAZZILLI


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