Letter | Published:

Changes in Cosmic Ray Intensity Associated with Magnetic Storms

Nature volume 158, pages 618619 (02 November 1946) | Download Citation



IT is usually supposed that the world-wide changes in cosmic ray intensity associated with a magnetic storm are due to variations in the earth's magnetic field produced during the storm. This seems to be excluded, however, by recent observations by Lange and Forbush1, who have found that the intensity varies (decreases and increases) even at Godhavn, which is situated at so high a geomagnetic latitude (80°) that the earth's magnetic field cannot possibly affect the intensity. Further, the variations cannot be due to changes in the solar magnetic field, because they are observed even at Huancayo, which has a low geomagnetic latitude (0.6°) so that it is reached only by the high-energy particles which are certainly not influenced by the solar magnetic field. Then the only possible explanation seems to be that the variations in cosmic radiation are due to changes in the earth's electrostatic potential.

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    and , Terr. Mag., 47, 331 (1942).

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    , Kungl. Svenska Vet. Akad., Handlingar III, Bd. 18, No. 3 (1939); No. 9 (1940).

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    , Arkiv. För mat. astr. fysik., Bd. 34, B, No. 1 (1946).

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    , Z. Phys., 107, 579 (1937); Nature, 143, 435 (1939).

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  1. Department of Electronics, Kungl. Tekniska Högskolan, Valhallavägen, Stockholm. Sept. 28.

    • H. ALFVÉN


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