Solar modulation during unusual minimum of solar cycle 23: Comparison with past three solar minima

摘要

We study the modulation of cosmic rays during the solar minimum, including declining phase, of solar cycle 23 and compare the results of this unusual period with the results obtained during the similar phases of previous solar cycles 20, 21 and 22. These periods consist of two A<0 and two A>0 polarity epochs of the heliospheric magnetic field. In addition to current sheet tilt, we utilize simultaneous solar and interplanetary plasma/field data. We study the relation between simultaneous variations in cosmic ray intensity and solar/interplanetary parameters during minimum, including declining phase of cycle 23. We compare these relations with those obtained for three previous solar cycles minima and declining phases. We observe certain peculiar features in cosmic ray modulation during this deep minimum of solar cycle 23. We discuss these results and some of their implications.