Corotating shock accelerated particles guided by wavy spiral magnetic fields in the solar wind at high heliographic latitudes

Abstract

We propose the persistent presence of randomly fluctuating, large-amplitude, long-timescale wavy spiral magnetic fields in the solar wind at all heliographic latitudes. These Alfvénic fluctuations can be generated by gradual evolution of solar coronal holes or by interplanetary Kelvin-Helmholtz instabilities occurring around the two conical interfaces at ∼±30° where strong wind shears appear quasi-periodically during the solar minimum. Using this scenario, we offer interpretations for several recent high-latitude observations of quasi-periodic (i.e., ∼26.6 days) energetic particle and cosmic ray modulations from Energetic Particle Composition instrument and Cosmic Ray and Solar Particle Investigation sensor systems aboard Ulysses spacecraft.