Harmonics of high-amplitude wave trains in cosmic ray intensity

Using the ground based neutron monitor data of Deep River, the high-amplitude anisotropic wave train events (HAE) in cosmic ray intensity have been investigated during the period 1991–1994. It has been observed that the phase of diurnal anisotropy for majority of HAE shifts towards later hours; whereas it remains in the corotational/18-h direction for some of the HAE cases. Further, for majority of HAE cases the amplitude of diurnal and semi-diurnal anisotropy significantly deviates from the annual average values. The phase of semi-diurnal and tri-diurnal anisotropy for all HAE cases has shifted to later hours. Furthermore, for tri-diurnal anisotropy the amplitude remains statistically the same. The occurrence of HAE is unaffected by the nature of the Bz component of IMF polarity.