Daily Variation in Cosmic Ray Intensity on Different Geomagnetic Conditions

Abstract

A new concept of data analysis has been attempted for studying the long/short term daily variations in cosmic ray (CR) intensity recorded with neutron monitors/meson telescopes. Fourier Technique has been applied on four different types of groups of days chosen according to their different geomagnetic conditions. The selected groups are 60 quietest days (60 QD), 120 quiet days (120 QD), continuous quiet days (CQD) and All Days (AD) in a year. CQD is a new set of days selected on the basis of Ap and Kp values. These are the days when transient magnetic variations are supposed to be regular and smooth continuously for a span of at least three days. The criteria of selection of CQD is based upon the mathematical manipulation with Ap index. The data of Deep River neutron monitoring station is used for the period 1985–1995, to investigate for a com-parative study of diurnal anisotropy in CR intensity on 60 QD, 120 QD, CQD and AD. It is observed that 60 QD are most suitable for the anisotropic studies on short/long term basis. The time/spatial variations in the amplitude and phase of the diurnal anisotropy become more pronounced for 60 QD for the period under investigation.

Influence of the Atmospheric Mass on the High Energy Cosmic Ray Muons during a Solar Cycle

“…However, differences in the observed rate of approximately 1.7% and 2.4% between 0.33 -11 and 0.33 -Jan , respectively, were found during some times. In some situations, above one percent is considered to be a large change, particularly in studying certain cosmic ray variations such as the diurnal variations and Forbush decreases [25,26]. The above results evidently indicated that one should carefully choose the suitable pressure correction prior to any cosmic ray modulation studies [27].…”

“…Moreover, some extraterrestrial factors affecting either the muon observations or the atmospheric pressure cannot be excluded [22]. It is obvious that the broad range of barometric coefficients supports the idea that the determination of over longer periods is of great importance for any cosmic ray detecting experiment and modulation study [16,21,[23][24][25]. Figure 3 demonstrates the diversity of using different values of to correct the effect of the atmospheric pressure on the muon rate.…”

Harmonics of high-amplitude wave trains in cosmic ray intensity

“…This variability is a reflection of the continually changing conditions in the interplanetary space [2]. The systematic and significant deviations in the amplitude/phase of the diurnal/semi-diurnal anisotropy from the average values are known to occur in association with strong geomagnetic activity [3]. Rao et al [4] have shown that the enhanced diurnal variation of high amplitude events exhibits a maximum intensity in space around the anti-garden hose direction and a minimum intensity around the garden hose direction.…”

Optimal control of population and coherence in three-level Λ systems

“…Search for an efficient scheme of population transfer is also one of the major goals of optimal control theory (OCT), a powerful and sometimes mathematically very sophisticated technique [16][17][18][19][20]. The OCT algorithm has been applied successfully to a broad variety of physical and chemical systems [21][22][23][24][25][26][27][28][29][30]. It intrinsically accounts for the quantummechanical interference between many pathways connecting initial and target state in a quantum system.…”