Rigidity dependence of 11 year cosmic ray modulation: Implication for theories

We use data obtained with the global network of detectors, with median rigidity (Rm) of response covering a wide range (1 to 200 GV), to derive the rigidity dependence of the 11 year modulation of galactic cosmic rays (GCR) for 4 sunspot cycles (20 to 23). We find that observed rigidity dependence is represented by a power law with negative exponents; the exponents do not depend on the solar magnetic polarity. However, the dependence on GCR rigidity is significantly flatter than is expected from the Quasi‐linear Theory of modulation formulated by Jokipii.