The main features of solar cycle 23, sun enters a period of intermediate and weak solar activity in terms of sunspot number. Based on the observation from Omniweb data centre for solar- interplanetary data , geomagnetic activity and monthly mean count rate of cosmic ray intensity (CRI) variation data from Oulu / Moscow/ Keil neutron monitors (Rc=0.80 GV , Rc=2.42 GV and Rc=2.29 GV,) during solar activity cycle 23 . The phase of minimum solar activity began in May 2005 and lasted for 4.5 years the unprecedented duration of the relative sunspot numbers falls. It is observed that the strength of the interplanetary magnetic field has been falling off to new low levels, and reduces the GCR entering inner- heliosphere and it is also found that SSN positive correlated with Kp and Ap and sunspot number, 10.7 cm solar radio flux, were inverse correlated with monthly mean count rate of cosmic ray intensity

1. IJSRD - International Journal for Scientific Research & Development| Vol. 2, Issue 07, 2014 | ISSN (online): 2321-0613
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Heliospheric Modulation of CRI Due to Solar Activity
Dr. B. K. Tiwari1
1
Department of Physics
1
A.P.S.University Rewa Madhya Pradesh 2
Rewa Engineering College Rewa, Madhya Pradesh
Abstract— The main features of solar cycle 23,
sun enters a
period of intermediate and weak solar activity in terms of
sunspot number. Based on the observation from Omniweb
data centre for solar- interplanetary data , geomagnetic
activity and monthly mean count rate of cosmic ray
intensity (CRI) variation data from Oulu / Moscow/ Keil
neutron monitors (Rc=0.80 GV , Rc=2.42 GV and Rc=2.29
GV,) during solar activity cycle 23 . The phase of
minimum solar activity began in May 2005 and lasted for
4.5 years the unprecedented duration of the relative sunspot
numbers falls. It is observed that the strength of the
interplanetary magnetic field has been falling off to new low
levels, and reduces the GCR entering inner- heliosphere and
it is also found that SSN positive correlated with Kp and Ap
and sunspot number, 10.7 cm solar radio flux, were inverse
correlated with monthly mean count rate of cosmic ray
intensity
Keywords: Cosmic ray intensity (CRI), Interplanetary
magnetic field (IMF), Solar magnetic field, sunspot number
(SSN)
I. INTRODUCTION
Solar cycle 23(of 12.5 years) have the most specific feature
and revealed its properties of evolution, which is entered in
the family of the intermediate-magnitude of solar activity, it
is farmally started in May 1996 reached its maximum in
term of relative sunspot numbers in April 2000 and
maximum 10.7cm solar radio flux observed in Feb 2002 i.e.,
the maxima of the two main indices were separated in time
as in the case of previous solar activity cycle. The complete
polarity reversal of solar magnetic field for solar structure at
(70ᵒ N and 70ᵒ S) occurred during July-December 2000. The
secondary maximum of solar cycle relative to sunspot
number, was observed in Nov 2001 .This solar cycle was
different other cycle is term of the number of active regions
before declining phase and stable (non flare) active regions,
which may be weaker circulation in the solar convection
zone during this cycle as compared to previous solar cycles
(Tiwari,B.K., et al.,2014). The total number of active region
in 23rd
solar cycle still behind previous solar cycle in term
of number of optical solar flare and major x-ray flare and the
last flare region with high flare appeared in the beginning of
December 2006 (after 6.6 years of maximum). The cycle is
characterized by abrupt decrease of the fluences (total daily
fluxes) before the decrease phase (July 2002), the decrease
in the flare activity reconnected in a considerable increase in
the number of days with quiet geomagnetic conditions.
In the extended solar minimum observed in 2009-
2010 counts of highly elevated fluxes of GCRs, this results
may be found considering the reduction in the total
heliospheric magnetic flux observed by interplanetary
spacecrafts, reduction in the magnetic flux comes during a
solar minimum, when the heliospheric magnetic field allows
better access to the inner heliospheric through gradient and
curvature drift of cosmic rays.(Jokipii et al 1977., Heber et
al 2009., Tiwari, et. al.,2014)
In a magnetic epoch like at present, when the
larged-scale solar magnetic fields are directed inward in the
north, we expect a more peaked time- profile for positive
charged GCRs. In contrast we expect a wider peak in the
time profile of positive charged GCRs in epochs when the
larged-scale solar magnetic field are directed outward is
north ( similar as 1970s &1990s). The reduction in
heliospheric flux and GCR drift patterns have caused the
extended solar minimum to be both elevated in dose rate &
prolonged compared to previous solar minimum this
provides optional conditions for the measurements of GCR(
Schwadron et. al.,2010, Zhao et. al.,2011 )
II. METHODLOGY
Data from three neutron monitor have been used for analysis
together with solar, IMF, solar wind, geomagnetic data from
internet sources (htpp://www.sec.noaa.gov/ace/)and
(ftp://ftp.ngdcnoaa.gov/stp/geomagnetic.data/). All results
on cosmic ray variation are obtained and analysis based on
the original sophisticated method
(I)
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Ap
SSN
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Ap
SSN

2. Heliospheric Modulation of CRI Due to Solar Activity
(IJSRD/Vol. 2/Issue 07/2014/151)
All rights reserved by www.ijsrd.com 669
(II)
Fig.1: (I)Monthly mean sunspot number with Ap and (Ii)
their correlation.
Fig. 2: Monthly mean count rate of CRI (Keil-red,Moscow-
violet,Oulu-Green)with Kp(blue) and Ap(orange) during
solar cycle 23
Fig. 3: Monthly mean count rate of CRI (Keil-red,Moscow-
violet,Oulu-Green)with sunspot number(blue) and 10.7cm
solar radio flux(orange) during solar cycle 23
Fig.4: (I) & (II)Correlation with monthly mean of Kp and
Ap during solar cycle 23
III. RESULT AND DISCUSSION
The cycle is characterized by an abrupt decrease of the
total daily fluxes of energetic particles and sun is entering a
period of intermediate and small solar activity cycles,
comparatively about 5 to 6 solar cycle .The decrease in the
flare activity resulted in a considerable increase in the
number of days with quiet geomagnetic conditions and a
significant decrease in the number of flare events will result
in a decrease in the number of stranger sporadic
geomagnetic disturbance conditions . A decrease in the
number of active regions may result in an increase in the
number of coronal holes and consequently, in the number of
recurrent high velocity solar wind streams, which will cause
relative in the number of recurrent minor geomagnetic
disturbance in the earth environment. The weaker solar
magnetic field will result in the shrinking, galactic cosmic
rays modulation 2006 in the interplanetary space & in a
significant increased in their intensity thought the entire
solar cycle, not only during the epoch of solar minimum.
IV. CONCLUSION
The solar cycle 23 is characterized by an abrupt decrease of
total daily fluxes of energetic particles , sun is entering a
period of intermediate and small solar activity,
comparatively about 5 to 6 solar cycles .The decrease in the
flare activity resulted in a considerable increase in the
number of days with quiet geomagnetic conditions, and a
decrease in the number of active regions may result in an
increase in the number of coronal holes and consequently in
the number of recurrent high velocity solar wind streams,
which will cause relative in the number of recurrent minor
geomagnetic disturbance in the earth environment. A
significant decrease in the number of flare events will result
in a decrease in the number of sporadic geomagnetic
disturbance conditions. The weaker solar magnetic field will
result in the shrinking, galactic cosmic rays modulation
2006 in the interplanetary space & in a significant increased
in their intensity thought the entire solar cycle, not only
during the epoch of solar minimum.
0
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Kp&Ap
CRI(Kiel,Oulu,Moscow)
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SSN&10.7cm
CRI(Kiel,Oulu,Moscow)
Kiel
Oul
u
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Kp
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Kp
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0 50 100 150 200
CRI(Oulu&Moscow)
SSN
Oulu
Moscow

3. Heliospheric Modulation of CRI Due to Solar Activity
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