1. Geomagnetic storm’s precursors observed with the Global Muon Detector Network – GMDN
ROCKENBACH, M.1; DAL LAGO, A.2; MUNAKATA, K.3; KATO, C.3; KUWABARA, T.4; BIEBER, J.4; SCHUCH, N.J.5; DULDIG, M.L.6; HUMBLE, J.E.6; AL JASSAR, H.K.7; SHARMA, M.M.7 and SABBAH, I.8,9
1Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraíba, São José dos Campos - SP, Brazil;
2National Institute for Space Research (INPE-MCT), São José dos Campos – SP, Brazil;
3Department of Physics, Shinshu University, Matsumoto, Japan;
4Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, USA;
5Southern Regional Space Research Center (CRS/CCR/INPE-MCT), Santa Maria, RS, Brazil;
6School of Mathematics and Physics, University of Tasmania, Hobart, Australia;
7Physics Department, Kuwait University, Kuwait ;
8Department of Natural Sciences, Collage of Health Sciences, the Public Authority of Applied Education and Training, Kuwait;
9Department of Physics, Faculty of Science, University of Alexandria, Alexandria, Egypt.

2. Solar activity cycle & GCR

3. Anchordoqui, L., et al., IJMP (2003)
Galactic Cosmic Rays (GCRs)
Bending here is due to the solar modulation which varies in solar cycle
~85 % protons
~10 % helium nuclei
a few % heavier nuclei
~1 % electrons
Observables
Energy spectrum
Elementary & isotopic compositions
Isotropic intensity
(GCR density)
Anisotropy
(GCR streaming)
 E-2.7
Anchordoqui, L., et al., IJMP (2003)

4. Cosmic ray observations with muon detector & neutron monitor
Ground-based detectors measure byproducts of the interaction of primary cosmic rays (mostly protons) with Earth’s atmosphere.
Neutron monitor detects neutrons produced by elastic scattering from atmospheric nuclei.
Muon detector measures muons produced by inelastic (strong) interaction.
E1ry (GeV) = 50~100, 1~30
observations of
inner heliosphere & space weather
Air shower array
Muon detector
Neutron monitor

5. (omnidirectional intensity)
GCR transport equation (Parker 1965)
: GCR density
(omnidirectional intensity)
SW convection
diffusion
Adiabatic cooling
Anisotropy ( ) tells us the spatial gradient ( )
which reflects the magnetic field geometry
: streaming
: anisotropy

6. Drift effect on the GCR transport
Difusion tensor
drift velocity
curvature drift
gradient drift
drift streaming
Reverses with B polarity  22y variation, T/A dependence

7. Drift model (Jokipii et al., ApJ, 213, 1977)
Solar wind V B
Neutral Sheet
(Current sheet)
Solar wind
source surface
Away
Toward   A T
V/ ~ 5AU
Wavy neutral sheet
Ballerina’s skirt

8. Drift model (Jokipii et al., ApJ, 213, 1977)
A>0 (Positive) Ω M TS NS
A<0 (Negative) Ω M TS NS

9. Drift model predictions
(Kota & Jokipii, 265, 573, 1983)
Reproduces the solar cycle variation of GCR density from the variation of NS tilt-angle.
Predicts local minimum (maximum) of GCR density on the NS for A>0 (A<0).
A < 0
A > 0
Toward
Away G
neutral sheet
neutral sheet G
Away
Toward

10. Solar activity cycle & GCR
（solar magnetic dipole reverses every 11 years） N S
However, this is only the variation of GCR density.
GCR wind also tells us the GCR gradient in 3D as a function of time.

11. Global Muon Detector Network
(GMDN)
Kaz. Munakata1, C. Kato1, S. Yasue1, J. W. Bieber2, P. Evenson 2, T. Kuwabara 2,
M. Rockenbach3, A. Dal Lago 4, N. J. Schuch 5, M. Tokumaru 6, M. L. Duldig 7, J. E. Humble 7,
I. Sabbah 8,9, H. K. Al Jassar 10, M. M. Sharma 10
GMDN collaboration
1 Shinshu University, JAPAN
2 Bartol Research Institute, USA
3 UNIVAP, BRAZIL
4 INPE, BRAZIL
5 CRS/INPE, BRAZIL
6 STE Laboratory, JAPAN
7 University of Tasmania, AUSTRALIA
8 College of Health Science, KUWAIT
9 Alexandria University, EGYPT
10 Kuwait University, KUWAIT
15 researchers from 10 institutes in 6 countries
working with 4 muon detectors in operation at…

12. Global Muon Detector Network 30 proportional counters
(GMDN)
Kuwait
(2006)
30 proportional counters
5m length 10cm diameter
9m2, 13,1h, 0,32
Nagoya (1969)
36m2 17 1h
0,15
Hobart(1992)
9m2 13 1h
0,3
São Martinho da Serra
Prototipe (2001)
Expansion I (2005)
Expansion II (2012)
4m2
28m2
36m2 9 17 1h
1, 10 e 60 min
0,34
0,2
0,15

13. ○□△display the asymptotic viewing directions of median energy cosmic rays corrected for the geomagnetic bending.
Thin lines indicate the spread of viewing direction for the central 80 % of the energy response to primary CRs.

14. GMDN data – October 29, 2003

15. Deriving first order anisotropy vector
(1) Barometric effect correction;
(2) Normalization
Data are normalized in relation to Nagoya vertical channel.
: 24 hour running average for jth channel of ith detector
: 24 hour running average for Nagoya (i=1), Vertical channel (j=1)
(3) Best-fit for cosmic ray density and anisotropy vector.
Cosmic Ray Density
Anisotropy vector
: coupling coefficient
We derive which minimize ….

16. GMDN data – October 29, 2003
11%

17. “Loss-cone” precursor
Cosmic ray Precursors
(%) -5 -4 -3 -2 -1 1
248
250
252
254
256
Nagoya V (60GeV)
Misato V (145GeV)
Sakashita V (331GeV)
SSC (01:39UT 9/9 1992)
Doy of 1992
“Loss-cone” precursor
(Nagashima et al., 1992)

18. “Loss-cone” precursor
Cosmic ray Precursors
“Loss-cone” precursor
(Nagashima et al., 1992)
Dorman et al. (2003)

19. Cosmic ray Precursors
Dorman et al. (2003)

20. Cosmic ray Precursors

21. Cosmic ray Precursors
December 14, 2006

22. Cosmic ray Precursors
December 14, 2006

23. Cosmic ray Precursors Rockenbach et al. GRL, 38, 2011 Loss cone
(deficit)
Enhanced Variance
shock reflection
(excess)
CR cylinder
Magnetic flux rope

24. Summary
Muon detectors measure muons produced by the interaction of high-energy (E > 1 GeV) primary cosmic rays (CRs) with the atmospheric nuclei.
Due to the high longitudinal momentum transfer to muons, their incident directions well preserve the incident direction of primary CRs ⇒ the multidirectional muon detector.
GMDN is a network of four muon detectors in Japan, Brazil, Australia, Kuwait, and capable for measuring CR intensities from many directions simultaneously.

25. Summary
We measure the CR streaming and CR precursors accurately with the GMDN and deduce the large-scale magnetic structure in the Space Weather:
The precursor is seen as the deficit intensity of CRs arriving from the sunward IMF: loss-cone (LC) precursor
CRs reflected and accelerated by the approaching shock are also observed as an excess intensity: enhanced variance precursory excess.
This is an alternative study, where we can estimate the arrival time of ICME using ground-based measurements.

26. Thank you!