Correlative analysis of long term cosmic ray variation in relation with sunspot number
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This academic article analyzes the correlation between cosmic ray intensity and sunspot number over solar cycles 22, 23, and the beginning of 24. The following key points are made: - Cosmic ray intensity and sunspot number show a high negative correlation, with cosmic ray intensity decreasing when sunspot number increases. - Solar cycle 23 was longer than cycle 22 at 12.6 years compared to 9.7 years. - Cycles 22, 23, and the beginning of 24 all show the pattern of anticorrelation between increasing then decreasing sunspot number and decreasing then increasing cosmic ray intensity. - The correlation coefficient between sunspot number and cosmic ray intensity for cycles 22-24 was found to be
![Advances in Physics Theories and Applications www.iiste.org
ISSN 2224-719X (Paper) ISSN 2225-0638 (Online)
Vol.22, 2013
10
Correlative Analysis of Long Term Cosmic Ray Variation in
Relation with Sunspot Number
UMA PANDEY
Department of Physics, MVM, Bhopal-462003 (M.P.)
Contact No: 07697312643 Email: uma.pandey185@gmail.com
MAHENDRA SINGH
Department of Physics, MVM, Bhopal-462003 (M.P.)
Contact No: 09425608307 Email: asbplin@rediffmail.com
PANKAJ K. SHRIVASTAVA
Department of Physics Govt. Model Science College ,Rewa(M.P.)-486001
Contact No: 09893328379 Email:pankaj_in_2001@rediffmail.com
Abstract
In this paper we will study about the relation between Cosmic ray Intensity(CRI) and Sunspot Number for solar
cycle 22, 23 and 24.For this we have taken the data of cosmic ray intensity from various neutron Monitor
stations .These neutron monitor stations are well maintained stations and provide reliable cosmic ray data for
variation study. A detail correlative study have been done by running cross correlation method. The cosmic ray
intensity and sunspot number shows high and negative correlation among themselves. Sunspot number shows
anti phase with Cosmic ray Intensity (CRI).
Keywords:- Cosmic –ray; Solar Cycle; Solar activity; Sunspot number
Introduction
In the past a lot of work has been done to correlate the solar parameters with cosmic ray intensity on long term
basis. In the recent past two ideas have motivated much to modulation research.The first originally proposed by
Lockwood (1960), is that the long term modulation of cosmic ray intensity i.e. 11 year variation result from
pileup of individual intensity decreases caused by shock’s and other disturbance in solar wind. The second major
idea is that gradient end curvature drifts, long neglected in theories of modulation may be significant and in some
cases dominant in governing the modulation of cosmic rays [1-3]. Generally sunspot numbers have been used as
a representative of solar activity index for various studies. Solar terrestrial relationships provide an important
factor to explain the aspects of the 11 and 22 year variation of galactic cosmic ray.The 11 year variation in
Cosmic ray Intensity observed on the earth is anti-correlated with sunspot number[4-5]. The Cosmic ray
Intensity curve follow a 22 year cycle with alternate maxima being flat topped and peaked as predicted by
models of Cosmic ray modulation based on the observed reversal of the sun’s magnetic field polarity after
every 11 year and curvature and gradient drifts in the large scale magnetic field of the heliosphere[6-10]..In this
paper we have made an attempt to derive the correlation between Sunspot number and Cosmic ray Intensity for
solar cycle22, 23 and 24.The solar cycle 22 have been started in the September 1986 and ended in the year
1996(May). The solar cycle 23 lasted in 12.6 years, beginning in May 1996 and ending in December 2008. The
maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period)
observed during the solar cycle 23 was 120.8, and the minimum was 1.7. There were a total of 805 days with no
sunspots during this cycle.[11]
METHOD OF ANALYSIS
In this paper we will find the correlation between Cosmic ray intensity and solar parameter sunspot number for
solar cycle22, 23 and 24(incomplete) .For this monthly mean values of sunspot number (Rz) are taken from the
Solar Geophysical Data books. The pressure corrected monthly mean value of cosmic ray data of Moscow,
Russia (Cutoff Rigidity=2.42GV) neutron monitor station have been taken for analysis. In this paper we will also
make comparative study of solar cycle 22, 23 and 24.
RESULTS AND DISCUSSION
Solar activity rises and falls with a period of about 11 years .The number of sunspots indicates the level of solar
activity. The emissions of matter and electromagnetic fields from the sun increases during high solar activity,
making it harder for Galactic Cosmic Ray to reach the earth. Cosmic ray intensity is lower when solar activity is
high and vice versa. The long term modulation of cosmic ray intensity has been studied by several scholars in
relation with sunspot number, and a high negative correlation is found between them. The fig.3 shows
correlation between sunspot number and Cosmic ray intensity(CRI) for solar cycle 22, 23 and 24(incomplete).](https://image.slidesharecdn.com/correlativeanalysisoflongtermcosmicrayvariationinrelationwithsunspotnumber-130830080644-phpapp01/85/Correlative-analysis-of-long-term-cosmic-ray-variation-in-relation-with-sunspot-number-1-320.jpg)
![Advances in Physics Theories and Applications www.iiste.org
ISSN 2224-719X (Paper) ISSN 2225-0638 (Online)
Vol.22, 2013
11
Figure 1 & 2 shows the linear plot of Sunspot number and Cosmic ray intensity with year. From fig.3&4 it is
clear that sunspot number and CRI are anti- correlated. Following conclusions can be drawn:
1) The solar 22 started in September 1986 and ended in May 1996.The total length of cycle 22 is 9.7 years. The
solar cycle 23 started in May 1996 and ended in December 2008 and total length of cycle is 12.6 yrs. Thus solar
cycle 23 is longer than solar cycle 22.The solar cycle 24 has started in the year 2008( December ) and is
incomplete.
2) The solar activity of solar cycle 22 shows increasing phase from 1986 to 1989 and then decreasing phase from
1989 to 1996.At the same time Cosmic ray intensity(CRI )decreases for the period 1986-1991 and shows
increasing phase from 1991 to 1996.Thus from the figure it is clear that as sunspot activity increases ,at the same
time Cosmic ray intensity (CRI) decreases. Thus both sunspot number and cosmic ray intensity shows anti-phase
with each other.
3) The solar activity of solar cycle 23 shows increasing phase from 1996 to 2000 and then decreasing phase from
2000 to 2008.At the same time CRI decreases for the period 1996-2000 and shows increasing phase from 2000
to 2008.Thus it is clear from fig 3. that for cycle 23 also sunspot activity and Cosmic ray intensity(CRI) are anti-
correlated.
4) The solar cycle 24 has started in the year 2008(Dec) and is incomplete. But it seems to be that solar cycle 24
is weaker in solar activity as comparison to cycle 22 and 23.
5)From fig.4 the correlation coefficient between sunspot number and Cosmic ray intensity (CRI) for solar cycle
22,23 and 24 is found to be -0.90057 which is highly negative correlated.
References
[1] Lockwood,J.A.,1960,J Geophysics.Res, 65,19
[2] Webber W.R. and Lockwood JA.,1988, Journal of Geophysical research,93 ,8735
[3] Sharma,N.I.,29th
International Cosmic ray Conference Pune ,2005,00, 101-104
[4] Forbush, S.E. 1954, J. Geophys. Res.,59,525
[5] Forbush,S.E. 1958, J. Geophys. Res.,63,651
[6] Dorman I V & Dorman L I, 1967,J Geophys Res(USA) ,72,1513
[7] Jokipii,J.R.,Thomas, B.T. 1981,Astrophys.. J.,243,1115
[8] Jokipii, J.R.,Levy, E.H.,Hubbard,W.B. 1977,Astrophys. J.,213,861
[9] Nagashima K & Morishitha I,Proc of 16th
ICRC, 1979,Tokyo,Japan,.3 ,325
[10] Gupta Meera,Mishra,V.K.,Mishra A.P. June 2006,Indian Journal of Radio
and space Physics, 35,167
[11] Solar Cycle 23 Wikipedia free encyclopedia](https://image.slidesharecdn.com/correlativeanalysisoflongtermcosmicrayvariationinrelationwithsunspotnumber-130830080644-phpapp01/85/Correlative-analysis-of-long-term-cosmic-ray-variation-in-relation-with-sunspot-number-2-320.jpg)
Correlative analysis of long term cosmic ray variation in relation with sunspot number
- 1. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.22, 2013 10 Correlative Analysis of Long Term Cosmic Ray Variation in Relation with Sunspot Number UMA PANDEY Department of Physics, MVM, Bhopal-462003 (M.P.) Contact No: 07697312643 Email: uma.pandey185@gmail.com MAHENDRA SINGH Department of Physics, MVM, Bhopal-462003 (M.P.) Contact No: 09425608307 Email: asbplin@rediffmail.com PANKAJ K. SHRIVASTAVA Department of Physics Govt. Model Science College ,Rewa(M.P.)-486001 Contact No: 09893328379 Email:pankaj_in_2001@rediffmail.com Abstract In this paper we will study about the relation between Cosmic ray Intensity(CRI) and Sunspot Number for solar cycle 22, 23 and 24.For this we have taken the data of cosmic ray intensity from various neutron Monitor stations .These neutron monitor stations are well maintained stations and provide reliable cosmic ray data for variation study. A detail correlative study have been done by running cross correlation method. The cosmic ray intensity and sunspot number shows high and negative correlation among themselves. Sunspot number shows anti phase with Cosmic ray Intensity (CRI). Keywords:- Cosmic –ray; Solar Cycle; Solar activity; Sunspot number Introduction In the past a lot of work has been done to correlate the solar parameters with cosmic ray intensity on long term basis. In the recent past two ideas have motivated much to modulation research.The first originally proposed by Lockwood (1960), is that the long term modulation of cosmic ray intensity i.e. 11 year variation result from pileup of individual intensity decreases caused by shock’s and other disturbance in solar wind. The second major idea is that gradient end curvature drifts, long neglected in theories of modulation may be significant and in some cases dominant in governing the modulation of cosmic rays [1-3]. Generally sunspot numbers have been used as a representative of solar activity index for various studies. Solar terrestrial relationships provide an important factor to explain the aspects of the 11 and 22 year variation of galactic cosmic ray.The 11 year variation in Cosmic ray Intensity observed on the earth is anti-correlated with sunspot number[4-5]. The Cosmic ray Intensity curve follow a 22 year cycle with alternate maxima being flat topped and peaked as predicted by models of Cosmic ray modulation based on the observed reversal of the sun’s magnetic field polarity after every 11 year and curvature and gradient drifts in the large scale magnetic field of the heliosphere[6-10]..In this paper we have made an attempt to derive the correlation between Sunspot number and Cosmic ray Intensity for solar cycle22, 23 and 24.The solar cycle 22 have been started in the September 1986 and ended in the year 1996(May). The solar cycle 23 lasted in 12.6 years, beginning in May 1996 and ending in December 2008. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle 23 was 120.8, and the minimum was 1.7. There were a total of 805 days with no sunspots during this cycle.[11] METHOD OF ANALYSIS In this paper we will find the correlation between Cosmic ray intensity and solar parameter sunspot number for solar cycle22, 23 and 24(incomplete) .For this monthly mean values of sunspot number (Rz) are taken from the Solar Geophysical Data books. The pressure corrected monthly mean value of cosmic ray data of Moscow, Russia (Cutoff Rigidity=2.42GV) neutron monitor station have been taken for analysis. In this paper we will also make comparative study of solar cycle 22, 23 and 24. RESULTS AND DISCUSSION Solar activity rises and falls with a period of about 11 years .The number of sunspots indicates the level of solar activity. The emissions of matter and electromagnetic fields from the sun increases during high solar activity, making it harder for Galactic Cosmic Ray to reach the earth. Cosmic ray intensity is lower when solar activity is high and vice versa. The long term modulation of cosmic ray intensity has been studied by several scholars in relation with sunspot number, and a high negative correlation is found between them. The fig.3 shows correlation between sunspot number and Cosmic ray intensity(CRI) for solar cycle 22, 23 and 24(incomplete).
- 2. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.22, 2013 11 Figure 1 & 2 shows the linear plot of Sunspot number and Cosmic ray intensity with year. From fig.3&4 it is clear that sunspot number and CRI are anti- correlated. Following conclusions can be drawn: 1) The solar 22 started in September 1986 and ended in May 1996.The total length of cycle 22 is 9.7 years. The solar cycle 23 started in May 1996 and ended in December 2008 and total length of cycle is 12.6 yrs. Thus solar cycle 23 is longer than solar cycle 22.The solar cycle 24 has started in the year 2008( December ) and is incomplete. 2) The solar activity of solar cycle 22 shows increasing phase from 1986 to 1989 and then decreasing phase from 1989 to 1996.At the same time Cosmic ray intensity(CRI )decreases for the period 1986-1991 and shows increasing phase from 1991 to 1996.Thus from the figure it is clear that as sunspot activity increases ,at the same time Cosmic ray intensity (CRI) decreases. Thus both sunspot number and cosmic ray intensity shows anti-phase with each other. 3) The solar activity of solar cycle 23 shows increasing phase from 1996 to 2000 and then decreasing phase from 2000 to 2008.At the same time CRI decreases for the period 1996-2000 and shows increasing phase from 2000 to 2008.Thus it is clear from fig 3. that for cycle 23 also sunspot activity and Cosmic ray intensity(CRI) are anti- correlated. 4) The solar cycle 24 has started in the year 2008(Dec) and is incomplete. But it seems to be that solar cycle 24 is weaker in solar activity as comparison to cycle 22 and 23. 5)From fig.4 the correlation coefficient between sunspot number and Cosmic ray intensity (CRI) for solar cycle 22,23 and 24 is found to be -0.90057 which is highly negative correlated. References [1] Lockwood,J.A.,1960,J Geophysics.Res, 65,19 [2] Webber W.R. and Lockwood JA.,1988, Journal of Geophysical research,93 ,8735 [3] Sharma,N.I.,29th International Cosmic ray Conference Pune ,2005,00, 101-104 [4] Forbush, S.E. 1954, J. Geophys. Res.,59,525 [5] Forbush,S.E. 1958, J. Geophys. Res.,63,651 [6] Dorman I V & Dorman L I, 1967,J Geophys Res(USA) ,72,1513 [7] Jokipii,J.R.,Thomas, B.T. 1981,Astrophys.. J.,243,1115 [8] Jokipii, J.R.,Levy, E.H.,Hubbard,W.B. 1977,Astrophys. J.,213,861 [9] Nagashima K & Morishitha I,Proc of 16th ICRC, 1979,Tokyo,Japan,.3 ,325 [10] Gupta Meera,Mishra,V.K.,Mishra A.P. June 2006,Indian Journal of Radio and space Physics, 35,167 [11] Solar Cycle 23 Wikipedia free encyclopedia
- 3. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.22, 2013 12 Graphs: Fig:1 Year Vs average yearly values of sunspot number(Rz) for solar cycle 22,23 and 24 Fig:2 Year Vs average yearly values of Cosmic Ray Intensity(Moscow Neutron Station) for solar cycle 22,23 and24
- 4. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.22, 2013 13 Fig:3 Shows cross-plot curve between yearly value of sunspot number(Rz) and Cosmic Ray Intensity (Moscow Neutron Station) for solar cycle 22,23 and24 Fig:4 Shows Correlation curve between yearly value of sunspot number(Rz) and Cosmic Ray Intensity(CRI) for solar cycle 22,23 and24
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