Hysteresis loops of Cosmic Ray intensity decreases versus solar and interplanetary parameters

Abstract

The purpose of this study was to examine the correlation between CR (Cosmic Ray) intensity and solar, interplanetary and terrestrial parameters. The hysteresis loops of (CR) versus those of several solar parameters showed narrow loops in even cycles 20, 22 and broad loops in odd cycles 19, 21, as also in the recent odd cycle 23. Hysteresis plots for CR versus interplanetary number density N and speed V were erratic and uncertain (broad and narrow, all mixed up). Plots of CR versus Interplanetary magnetic field (IMF) B seemed to be narrow for even as well as odd cycles. Hysteresis loops between CR and other interplanetary parameters were not clear-cut. The same was true for terrestrial parameters. During sunspot maximum years 2000–2003 of cycle 23, there is a double peak structure in all parameters. Whereas CR have a peak spacing of ~30 months, sunspots and Tilt angle have a spacing of only ~20 months. The solar open magnetic flux and the Voyager 1 magnetic field have a spacing of ~25 months. The solar polar magnetic field reverses later than the first peak of all parameters and hence, could not be a direct cause (as if effect started before the cause and lasted for several months more after the cause disappeared). It seems that CR modulation is mainly guided by magnetic configurations deep in the heliosphere, which may not have a simple relationship with parameters near Earth or near Sun.