The secular imprint of the interplanetary magnetic field drift on 10Be data

Abstract

We perform an analysis of the evolution of the 10Be and the geomagnetic aa index in the common period 1868-1990. Correlations of the whole period do not produce a very high correlation coefficient (r = 0.45). However, separating the data sets according to the different phases of the solar cycle leads to a good correlation between 10Be and aa for negative (A < 0) polarity and a low correlation for the positive (A > 0) polarity. The 10Be data is found to be statistically different between positive and negative polarity times. However, no difference is found for the aa index of the two alternative solar magnetic polarities. These facts evidence the solar magnetic field drift effects on cosmic rays over the 11 solar cycles spanning this work. Copyright 2004 by the American Geophysical Union.