Cosmic ray anisotropy along with interplanetary transients

نویسندگان

  • R. K. Mishra
  • R. Agarwal
چکیده

Abstract The present work deals with the study of first three harmonics of low amplitude anisotropic wave trains of cosmic ray intensity over the period 1991-1994 for Deep River neutron monitoring station. It is observed that the diurnal time of maximum remains in the co-rotational direction; whereas, the time of maximum for both diurnal and semi-diurnal anisotropy has significantly shifted towards later hours as compared to the quiet day annual average for majority of the LAE events. The occurrence of low amplitude anisotropic wave trains is dominant during average solar wind velocity but their appearance during high-speed solar wind streams is also possible. The disturbance storm time index i.e. Dst remains consistently negative only throughout all the low amplitude wave train events. The phase of tri-diurnal anisotropy for LAE events is found to shift towards earlier hours with the increase of geomagnetic activity index Ap, showing a significant anti-correlation.

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تاریخ انتشار 2008