Investigating the influence of geometry of the heliospheric neutral current sheet and solar activity on modulation of galactic cosmic rays with a method of main components

Abstract

The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.

Keywords

• cosmic ray modulation
• interplanetary magnetic field
• neutral current sheet
• solar activity