Study of Higher Harmonics of Cosmic Ray Intensity on Quiet Days at Deep River Neutron Monitoring Station

Abstract

The cosmic ray (CR) intensity data recorded with Deep River Neutron Monitoring Station have been investigated on quietest days (QD) for higher harmonics of daily variation during solar cycle 21 and 22. It has been observed that inspite of the abrupt change in the amplitude and phase of tri-diurnal and quart diurnal anisotropy in CR intensity, the amplitude of third harmonic is quite significant throughout the period of investigation with larger amplitude during the year 1980 and 1985. Thus, tri-diurnal anisotropy clearly shows 11 year variation at mid latitude neutron monitoring station.