Low-energy Solar Cosmic Rays and the Geomagnetic Storm of May 12, 1959

Download or read book Low-energy Solar Cosmic Rays and the Geomagnetic Storm of May 12, 1959 written by J. R. Winckler and published by . This book was released on 1960 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: During a strong geomagnetic storm on May 11-12, 1959, and following a class 3+ chromospheric solar flare on May 10, a large intensity of low-energy solar cosmic-ray protons was observed in a balloon flight at 30-km altitude at Minneapolis, Minnesota. This paper reports the results obtained with an ion chamber, Geiger counter, and scintillation counter. The proton flux of energy above 100 Mev varied from 52 to 1.7/cm2-sec-steradian during the time 0400 to 1800 UT on May 12. The spectrum obtained with the counting instruments is consistent with detailed emulsion studies and has the form N(>E)=CE−7. With E in Mev, [gamma] varies from 5 to 2 during the above time period. The scintillation counter showed excess [gamma] radiation from the nuclear effects of the cosmic-ray protons, and intense bursts of auroral X rays, particularly at 0835 UT on May 12. The solar optical and radio features of the flare are discussed, and the relationship of the polar-cap ionospheric blackout to the Minneapolis measurements is considered. The cosmic-ray protons at Minneapolis are measured at energies well below the normal Störmer cutoff for that latitude. Several theories on this subject are presented.