Correlations between the Very Low Frequency Emissions and the Magnetic and Cosmic Ray Storms

Abstract

The number spectrum of EAS has been found to extend to showers of more than 10/sup 10/ particles without noticeable increase in steepness. The logarithmic slope has some uncertainty because of an unknown variation of lateral distribution near the axis with shower size; the corrected value of gamma is about 1.7 for 6 x 10/sup 6/ 10/sup 7/) seem to exhibit substantial anisotropy, but the statistical significance of this observation is not very great. The persistent feature is a pronounced minimum around 15 hours local sidereal time. In the showers of 5 x 10/sup 6/ 10/sup 8/ this minimum appeared to be associated with a large first harmonic (35%). A minimum in the third quadrant also appears in the MIT Agassiz data for showers of N > 10/sup 8/, and in the MIT Volcano Ranch data, as wellmore » as in Japanese data on mu rich'' showers, mu - less'' showers, and multiple penetrating particles observed underground. Fourier analysis of the frequencies of smaller showers reveals no second harmonics, but a possibly significant first harmonic of amplitude about 0.4% with maxima in the range 13 to 20 hours local sidereal time, for EAS of 10/sup 4/ < N < 10/sup 6/ particles. Because of the complexity of solar periodic atmospheric effects on EAS, this apparent anisotropy of the primaries may be spurious; but is is suspicious that many experimenters in different places on the earth have found maxima at approximately the same local sidereal time, both in the rates of small EAS and in the background cosmic-ray intensity. (auth)« less