Heliosphere modulation of Primary Cosmic Rays for the AMS-02 mission (original) (raw)

Based on the observation from Omniweb data centre for solar- interplanetary data and monthly mean count rate of cosmic ray intensity (CRI) variation data from Oulu / Moscow neutron monitors during 23/24 solar cycle. It is observed that Solar variability controls the structure of the heliosphere and produces long-term as well as short-term changes in cosmic ray intensity, during minimum solar activity period the sun is remarkably quiet and the strength of the interplanetary magnetic field has been falling off to new low levels, reduces the GCR entering inner- heliosphere and it is high anti-correlation between sunspot number & GCR flux. It is also found that 10.7 cm solar radio flux, velocity of solar wind and the strength and turbulence of the interplanetary magnetic field with count rate of cosmic ray intensity are inverse correlated.

After six years of continuous observations in space, the Alpha Magnetic Spectrometer experiment has released new data on the temporal evolution of the proton and helium fluxes in cosmic rays. These data revealed that the ratio between proton and helium fluxes at the same value of rigidity R=p/Z (momentum/charge ratio) is not constant at R<3 GV. In particular, the ratio is found to decrease steadily during the descending phase of Solar Cycle 24 toward the next minimum. We show that such a behavior is a remarkable signature of the β × λ(R) dependence in the diffusion of cosmic rays in heliosphere, where β is their adimensional speed and λ(R) is their mean free path, a universal function of rigidity for all nuclei. This dependence is responsible for distinctive charge/mass dependent effects in the time-dependent modulation of low-rigidity particles.

The solar modulation effect of cosmic rays in the heliosphere is an energy-, time-, and particle-dependent phenomenon that arises from a combination of basic particle transport processes such as diffusion, convection, adiabatic cooling, and drift motion. Making use of a large collection of time-resolved cosmic-ray data from recent space missions, we construct a simple predictive model of solar modulation that depends on direct solar-physics inputs: the number of solar sunspots and the tilt angle of the heliospheric current sheet. Under this framework, we present calculations of cosmic-ray proton spectra, positron/electron and antiproton/proton ratios, and their time dependence in connection with the evolving solar activity. We report evidence for a time lag D =  T 8.1 1.2 months, between solar-activity data and cosmic-ray flux measurements in space, which reflects the dynamics of the formation of the modulation region. This result enables us to forecast the cosmic-ray flux near Earth well in advance by monitoring solar activity.

The structure of the heliosphere controls by solar outputs and their variability produces changes in cosmic ray intensity on long-term and short-term basis. Based on the observation from Omniweb data centre for solar- interplanetary data and monthly mean count rate of cosmic ray intensity (CRI) variation data from neutron monitors were used during 1996-2014. It is observed that during declining phase of solar cycle 23and ascending phase of 24 solar cycle , the sun is remarkably quiet and the strength of the interplanetary magnetic field has been falling off to new low levels , reduces the GCR entering inner- heliosphere and it is high anti-correlation has been found between sunspot number & GCR flux. It is also found that count rate of cosmic ray intensity and solar- interplanetary parameters were inverse correlated and these solar indices were positive correlated.