Relations between terrestrial magnetism and cosmic‐ray intensity

Abstract

Certain relations between the variations of the Earth's horizontal magnetic force H and of the observed cosmic‐ray ionization J have been found in the continuous registrations of the cosmic‐ray ionization on the Hafelekar, 2300 meters above sea‐level (near Innsbruck, Austria) during the year 1936–37 as follows:(1) A positive magnetic effect, ME1 is indicated during magnetic storms with increase of J associated with increase of H and vice versa. A similar effect has been noticed rather often also in the daily mean values of J and H during magnetically undisturbed days. ME1 amounts to +0.57 per mille of the cosmic‐ray ionization for an increase of the horizontal force by one γ (0.00001 gauss).(2) The analysis of the daily mean values for one year discloses a second effect, ME2, of opposite sign (increase of H accompanied by decrease of J) and smaller than ME1. ME2, for the average of the year 1936–37, is about −0.20 per mille per γ.(3) A similar negative magnetic effect, ME3, is found from the strong correlation between the diurnal variation of H and J; ME3= −0.2 per mille per γ.(4) Another negative effect, ME4, can be derived from the anti‐parallel variations of the monthly means of H and J (seasonal curves); ME4 = −1 per mille per γ.The three first‐mentioned effects can be explained qualitatively by adopting the hypothesis of the electronic ring‐currents in the outer space around the globe. The seasonal effect is not yet explained and it seems possible that its connection with terrestrial magnetism is accidental, in spite of the strong correlation.