Cosmic ray modulation observed in stratospheric measurements
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Cosmic ray modulation observed in stratospheric measurements Stozhkov Y.I., Svirzhevsky N.S., Bazilevskaya G.A., Makhmutov V.S., Svirzhevskaya A.K., Logachev V.I. P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninsky Prospect 53, 119991 Moscow, Russia 21 st ECRS Slovakia, Kosice, 9-12 September 2008
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Cosmic ray modulation observed in stratospheric measurements. Stozhkov Y.I., Svirzhevsky N.S., Bazilevskaya G.A., Makhmutov V.S., Svirzhevskaya A.K., Logachev V.I. P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninsky Prospect 53, 119991 Moscow, Russia. - PowerPoint PPT Presentation
Transcript of Cosmic ray modulation observed in stratospheric measurements
Cosmic ray modulation observed in stratospheric measurements
Stozhkov Y.I., Svirzhevsky N.S., Bazilevskaya G.A., Makhmutov V.S., Svirzhevskaya A.K., Logachev V.I.
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninsky Prospect 53, 119991 Moscow, Russia
21st ECRS Slovakia, Kosice, 9-12 September 2008
IntroductionThe data on galactic cosmic ray (CR) fluxes
measured in the Earth’s atmosphere at polar (northern and southern) and middle latitudes during the period of about 50 years are presented.
These data show long-term modulation processes in the several 11-year solar activity cycles. Minimum and maximum periods are discussed and comparison with the data obtained at the spacecraft of Voyager – 1 and Voyager – 2 is made.
The analysis of solar activity in the previous solar cycles gives the proof that the 24th solar cycle will be very low. It is possible that we meet new grand solar activity minimum, like Maunder one in 1645-1715.
Fig.1. Time dependence of CR flux at maximum of absorption curve in the atmosphere Nmax (monthly averages) obtained at the northern polar latitude (Rc = 0.5 GV, green curve), southern polar latitude (Mirny station, Antarctic, Rc = 0.04 GV, blue curve), and at middle northern latitude (Rc = 2.4 GV, red curve). Brown horizontal bar is expected CR flux.
1.5
2.0
2.5
3.0
3.5
1955 1965 1975 1985 1995 2005 2015
Year
Nm
ax, с
m-2
s-1
Rc= 2.4 GV
Rc= 0.04 and 0.5 GV
0
50
100
150
200
1600 1700 1800 1900 2000
Year
su
ns
po
t n
um
be
r
Fig.2. Time dependence of solar activity (Douglas V. Vogt, Kenneth H. Shatten.Group Sunspot Number: A new Solar Activity Reconstruction, Solar Physics, 179, No. 1, pp. 189-219 (1998); http://sidc.oma.be/index.php3).
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0
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40
1961 1962 1963 1964 1965 1966 1967 1968
Year
su
ns
po
t h
elio
lati
tud
e
19 - 20 s olar ac tivity c yc les
Fig. 3. Heliolatitudinal distribution of sunspots during the end of 19th and the start of 20th solar cycles (1961 – 1967).
0
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1963 1964 1965 1966 1967
Year
Su
ns
po
t n
um
be
r
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0
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40
50
he
liola
titu
de
19 - 20 solar cycles t = 3 months
Fig. 4. Sunspot number in 1963 -1966 (monthly averages, red points and curve; smoothed data with 3 month, blue curve; left vertical axes). Heliolatitudes of sunspots of new 20th solar cycle (green points and left vertical axes). Brown circle shows the solar activity minimum period.
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-10
0
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2003 2004 2005 2006 2007 2008 2009
Year
su
sp
ot
he
liola
titu
de
23 - 24 solar activity cycles
Fig. 5. Heliolatitudinal distribution of sunspots in 2003 – 2008.Blue points show heliolatitudes of sunspots of new 24th solar cycle.
Fig. 6. Solar activity in recent time (monthly averages, red points and curve; smoothed data with 3 points).
0
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2005 2006 2007 2008 2009
Year
su
ns
po
t n
um
be
r
-20
-10
0
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su
ns
po
t h
elio
lati
tud
e
23 - 24 solar activity cycles
tsm = 3 months
0
20
40
60
80
100
120
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160
180
1995 2000 2005 2010 2015
Year
Rz
Fig. 7. Solar activity in 1996 – 2008 (red points), prognosis of solar activity (blue curve- this report, green curve- http://www.swpc.noaa.gov/SolarCycle/index.html).
0.0
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0.4
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1.0
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1975 1980 1985 1990 1995 2000 2005 2010
Year
V1,
V2,
co
un
t/s
1.5
2
2.5
3
3.5
4
4.5
5
Nm
ax,
cm
-2 s
-1
V2 V1
Nmax
Fig. 8. Time dependences of CR fluxes, obtained in our experiment in northern and southern polar regions at 1 a.u. and in the heliosphere from 1 a.u. up to ~ 107 a.u. (V1 and V2 data, Ep > 70 MeV)).
2
2.5
3
3.5
4
4.5
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
Nm
ax, c
m-2
s-1
0.4
0.6
0.8
1.0
1.2
1.4
J(>
70
Me
V),
co
un
t s
-1
V1
V2
Nmax
Fig. 9. Step-like changes of CR fluxes near the Earth (red points) and in the outer heliosphere (green triangles and blue squares). Horizontal bars show the periods of ~ constant in time of CR fluxes.
0.2
0.4
0.6
0.8
1.0
1.2
1.4
2004 2005 2006 2007 2008 2009
Year
V1
, V2
, co
un
t s
-1
2
2.5
3
3.5
4
4.5
5
Nm
ax, c
m-2
s-1
V2
V1
Mu
Mi
Fig. 10. Time dependences of CR fluxes observed in the atmosphere and outer heliosphere in recent time in detail.
0
20
40
60
80
100
120
0 20 40 60 80 100 120
r , au
A, %
1st step
2nd step
Fig. 11. Amplitudes of step-like changes observed at 1 a.u. and in outer heliosphere.
Conclusion
- From the middle of 2007 cosmic ray flux has a prolonged maximum near the Earth’s orbit;
- It is probably that 24th solar cycle will have low solar activity level;
- Analysis of step-like changes observed in cosmic rays for recent years (2004-2008) shows that the modulation of cosmic particles will be over at the distances ~ (110 – 115) a.u.
