Research Journal of Physical Sciences ______ISSN 2320–4796 Vol. 2(3), 4-8, June (2014) Res. J. Physical Sci.

Study of variation in Intensity due to Solar-Interplanetary activity between 1996-2013 B. K. Tiwari 1, B.R. Ghormare 2, P.K. Shrivastava 3 and D.P. Tiwari 4 1Department of , Jawahar Lal Nehru College of Technology, Rewa, MP, INDIA 2Department of Physics, Rewa Engineering College, Rewa, MP, INDIA 3Department of Physics, Model Science College, Rewa, MP, INDIA 4 Department of Physics, A.P.S. University, Rewa, MP, INDIA

Available online at: www.isca.in Received 22 nd May 2014, revised 2nd June 2014, accepted 4 th June 2014

Abstract Solar outputs and their variations are responsible to produce changes in cosmic ray intensity (CRI) both on short-term as well as on long–term basis. It is observed that number; 10.7 cm solar radio flux, coronal mass ejections (CMEs) and solar flares are the causal link to solar activity. Moreover, coronal mass ejections are associated with a variety of interplanetary plasma and field disturbances. Based on the observation from Omniweb data centre for solar- interplanetary data activity and monthly mean count rate of cosmic ray intensity (CRI) variation data from neutron monitors (Moscow, Oulu, Keil) during the period of 1996-2013.We observed a record high value of cosmic ray intensity with low values of solar interplanetary activity parameters during minimum of 23 and ascending phase of 24. Statistical techniques are used to correlate data of solar interplanetary and count rate of cosmic ray intensity i.e. better anti-correlated with solar activity parameters.

Keywords: Heliospheric magnetic field (HMF), Galactic cosmic ray (GCR), Magnetic clouds (MCs), Coronal mass ejections (CMEs).

Introduction shocks 5. The interplanetary magnetic field emanated from the Sun changes with the solar activity cycle, changing variations in The intensity of galactic cosmic rays is subjected to heliospheric speed of particle transport process such as convection diffusion modulation under the influence of solar outputs and their drift and adiabatic deceleration 6. variations. Cosmic rays (charge particles) are scattered by irregularities in the structure of heliospheric magnetic field and Solar wind (SW) density, pressure and strength of interplanetary undergo convection and adiabatic deceleration in the expanding magnetic field (IMF) all are their lowest values and measured a solar wind changes in the heliospheric conditions as produced record excess GCR intensity was accompanied by the relative by the solar activity. Variation in cosmic ray is usually caused decrease of the anomalous cosmic rays (ACRs), quickly by transient interplanetary events, which are related to coronal decreased with energy about zero for low latitudes neutron mass ejections (CMEs). Scott. Forbush established the monitors during period between solar minimum of cycle 23 and correlation between world-wide decreases in cosmic ray ascending phase of 24. Solar and heliospheric conditions make 1 intensity and geomagnetic storms and the sunspot cycle ( ̴̴ 11 this period interesting for the study of cosmic rays modulation years) in GCRs intensity i.e., its variation in the opposite phase with indices of solar activity and heliospheric parameters. with sunspot number and which can be understood by the are low or absent, strength of the HMF was transport of GCRs through the model of heliospheric magnetic exceptionally low between cycle 23 and 24 minimum and solar 2 field (HMF) . During high solar activity magnitude of the HMF interplanetary activity parameters where significant different increases due to larger number of CMEs ejected from the sun from the previous solar minimum 7. The main unusual features in (which occurs each ̴̴ 11- years sunspot cycle), therefore solar the GCR intensity in this anomalous period are excess of the magnetic field more effective at sweeping GCRs out of the inner maximum intensity during 2009-2010, the sun was much heliosphere which causes a strong reduction in GCR flux and quieter, the heliospheric magnetic field was weaker and reproduce the ̴ 22 years GCR modulation using a time- observed higher cosmic ray diffusion coefficient allows an dependent modulation model. In the interplanetary space GCR increase in GCR intensity 8,9,10 . can be modulated by sporadic emission of clouds of magnetized 3, 4, plasma and produce terrestrial geomagnetic storms . Small Data analysis decreases in galactic cosmic rays are associated with magnetic clouds (MCs) are not preceded by shocks where as large In order to study the long term variation in cosmic ray through decreases are associated with that MCs are preceding by the years 1996-2013 ,monthly mean values of cosmic rays data

International Science Congress Association 4 Research Journal of Physical Sciences ______ISSN 2320–4796 Vol. 2(3), 4-8, June (2014) Res. J. Physical Sci. were used observed by neutron monitors http://www.nmdb.in from National Geographical Data Centre (NGDC) and analyzed (Moscow (Rc=2.32GV), Oulu (Rc=0.81GV) and Kiel solar interplanetary data from Omniweb data base (Rc=2.39GV). In this study we also used data of mean monthly http://www.omniweb,gsfc.nasa.gov.in . sunspot numbers (SSN), monthly group index taken

9800 140 9600 120 9400 100 9200 SSN 9000 80 8800 60 8600 40 8400 20

count ratecount of cri (moscow) 8200 moscow 8000 0 1995 2000 2005 2010 2015 SSN year (a) Variation in count rate of cri (moscow) with SSN during 1996-2013

11000 2 10500 1.5 10000 1 9500 0.5 9000 0 8500 Bz 8000 -0.5 7500 -1 7000 -1.5

count ratecount of cri (moscow) moscow 1995 2000 2005 2010 2015 Year Bz

(b) Variation of count rate of cri (moscow) and Bz during 1996-2013

9800 600 9600 550 9400 500 9200 450 9000 400 8800 8600 350 8400 300 8200 250 Solarwind velosity 8000 200 moscow count ratecount of cri (moscow) 1995 2000 2005 2010 2015 SWV

Year (c) Effect of solar wind velosity on cri (moscow) during 1996-2013 Figure-1 (a,b,c,) Long-term variation in cosmic ray intensity as observed by Moscow with solar-interplanetary activity indies (SSN,Bz,SWV) during 1996-2013

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11000 300

10000 250

9000 200

8000 150

7000 100

count ratecount of cri (moscow) 6000 50 SSN&10.7cm SSN&10.7cm solar radioflux 5000 0

1996 1999 2002 2005 2008 2011 year Year

Figure-2 (d) 8000 300 7500 250 7000 200 6500 6000 150 5500 100 5000 Count Count of rate (oulu) cri 50 10.7cm SSN & solar radioflux 4500 4000 0 year Oulu SSN 1996 2001 2006 2011 10.7cm SF Year

Figure-2(e) 12000 300 11000 250 10000 9000 200 8000 150 flux 7000 100 6000 50

Count Count of rate (kiel) cri 5000

4000 0 10.7cm SSN & solar radio year Kiel 1996 1999 2002 2005 2008 2011 Year SSN Figure-2(f) Figure-2 (d,e,f,) Long-term variation in cosmic ray intensity as observed by Moscow Oulu Keil with solar- activity indies (SSN,10.7 cm solar radio flux) during 1996-2013

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7000 200 6800 180 6600 160 6400 140 6200 120 6000 100 5800 80 CRI (oulu) CRI 5600 60 5400 40 5200 20 SSN&10.7cm Solar radioflux 5000 0 Oulu CRI 1995 2000 2005 2010 2015 SSN year 10.7cmsolar radio flux Figure-3(g) 12000 200 180 10000 160 8000 140 120 6000 100 80 CRI (kiel) CRI 4000 60 2000 40 20 0 0

1995 2000 2005 2010 2015 10.7cm SSN& solar radioflux Kiel CRI Year SSN 10.7cmsolar radio flux Figure-3(h) 9800 200 9600 180 9400 160 9200 140 120 9000 100 8800 80

CRI (moscow) CRI 8600 60 8400 40 8200 20 SSN&10.7cm SSN&10.7cm solar radioflux 8000 0 1995 2000 2005 2010 2015 moscow CRI Year SSN 10.7cmsolar radio flux Figure-3(i) Figure-3 (g,h,i,) Long-term variation in cosmic ray intensity as observed by Oulu Keil Moscow with solar-interplanetary activity indies during 1996-2013

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Result and Discussion to increase in interplanetary magnetic field and solar wind velocity, although the correlation are poor. Cosmic ray intensity variation are produced by the transient disturbance like traveling interplanetary shocks, are produced by References coronal mass ejection and events vary with solar activity at the different phases of the sun spot cycle. Large decreases in CRI 1. Forbush, Physics Rev. 51 ,1108-1109, (1937) are associated with MCs preceded by shocks where as small 2. Parker E.N., Planet. Space Sci , 13 ,9-49,doi:10.1016/0032- decreases are associated magnetic clouds are not preceded by 0633(65) 90131-5, (1965 ) shocks. The variation cosmic ray intensity are inversely correlated with solar activity indices and these variations are 3. Van Allen, by book biographical memories ( 1985 ) produced by solar wind velocity (V) is related to convection, 4. Burlaga L.F. and Chang. G., J. Geophys, Res ., 93 , 2511- diffusion depends on the interplanetary field strength (B) and its 2518 ( 1988 ) fluctuations, and the tilt of the heliosphereic current sheet.

5. Tiwari B.K., Thesis Submitted to APSU, ( 2010 ) Conclusion 6. Burlaga L.F., Sitter E., Mariani F., Schwenn R., J. Geophys. Res., 86 , 6673 (1981) Cosmic ray intensity variations based on variation with Solar and interplanetary indices as well as tilt of the heliosphereic 7. Potgieter M.E, J. Atmos. Sci-Terr. Phys., 70 , 207 (2008) current sheet and intensity variations of interplanetary magnetic 8. Potgieter M.E., Plant Space Res., 46 , 402 (2010) field (IMF). Variation in CRI are closely related with halo

CMEs associated with X-ray solar flares of different categories 9. Ahluwalia H.S. and Yghuhay R.C., AIP Conf. Proc., and interplanetary shocks .during the minimum solar activity 1216 , 699 (2010) phase decrease rate of cosmic ray intensity is faster with respect 10. Tiwari B.K., Ghormare B.R., Shrivastava P.K., Tiwari D.P., Res. J. Physical Sci., 2(2), 9-12, (2014)

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