Precursor signatures of storm
sudden commencement observed
by a network of muon detectors
C. R. BRAGA 1, A. DAL LAGO 1, M. ROCKENBACH 2 , N. J. SCHUCH 3, L. R. VIEIRA 1,
K. MUNAKATA 4, C. KATO 4 , T. KUWABARA 5, P. A. EVENSON 5, J. W. BIEBER 5,
M. TOKUMARU 6, M. L. DULDIG 7, J. E. HUMBLE 7, I. S. SABBAH 8, H. K. AL JASSAR 9, M. M. SHARMA 9
1 National
Institute for Space Research, São Jose dos Campos, Brazil
do Vale do Paraíba ,São Jose dos Campos, Brazil
3 Southern Regional Space Research Center, Santa Maria, Brazil
4 Physics Department, Shinshu University, Matsumoto, Japan
5 Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, USA
6 Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan
7 School of Mathematics and Physics, University of Tasmania, Tasmania, Australia
8 Department of Natural Sciences, College of Health Sciences, the Public Authority of Applied Education and Training, Kuwait - Department of Physics, Faculty
of Science, Alexandria University, Alexandria, Egypt
9 Physics Department, Faculty of Science, Kuwait University, Kuwait City, Kuwait
2 Universidade
E-mail: crbraga@dge.inpe.br
Global Muon Detector Network (GMDN)
6x6
3x3
4x7
3 x 3 (4 x 4)
Nagoya
Kuwait
Hobart
São2Martinho
da Serra
Detectors photographs (except Sao Martinho da Serra): private communication with Prof. K. Munakata, 2010
and Prof. I. Sabbah, 2011
Background source: http://earthsatellitemaps.com/wp-content/uploads/2009/06/mapofearth.jpg, 2010
Source: Yashin et al. (2006).
Objective
To study the possibility of observing cosmic ray
precursors of a weak geomagnetic storm registered in
November 24th 2008 with storm sudden
commencement (SSC) at 23:51 UT.
Methodology
- Pressure effect correction;
- Temperature effect correction;
- Trailing moving average;
- First order anisotropy;
- Normalization by statistical error.
Negative temperature effect
ΔN T = N  βT  ΔH
Deviation Na V(%)
∆H: deviation of
the altitude of
100 hPa
Dev(%)=-5.9 (%/km) ∙ ∆H (km) + 97%
Correlation=-0.95
Altitude (km) of 100 hPa layer
NTEMPERATURE _ CORRECTED = N NOTCORRECTED  ΔN T
Temperature effect correction
Deviation Na V(%)
Dev(%)=-5.9 (%/km) ∙ ∆H (km) + 97%
Correlation=-0.95
Nagoya: α≥ 0.95
-6.7 ≤ β ≤ -5.9 %/km
São Martinho da Serra : α≥ 0.49
-4.8 ≤ β ≤ -3.7 %/km
Hobart: α≥ 0.72
-5.0 ≤ β ≤ -3.6 %/km
Kuwait: α≥ 0.89
-7.3 ≤ β ≤ -6.1 %/km
Altitude (km) of 100 hPa layer
β: regression coefficient (slope)
α: correlation coefficient
High-altitude measurements sites
High-altitude pressure measurements sites
Name
Geographic coordinates
Muon station
Approx. distance
(km)
(degrees)
Shionomisaki
33.5 N; 140.1 E
200
Tateno
36.0 N;140.1 E
Wajina
37.4 N; 136.9 E
Porto Alegre
30.0 S; 308.8 E
São Martinho da Serra
260
Kuwait
29.2 N; 48.0 E
Kuwait
10
Hobart
42.8 S; 147.5 E
Hobart
30
Nagoya
400
300
WINTER
SUMMER
WINTER
Hobart Dev V(%)
Nagoya Dev V(%)
Seasonal temperature effect correction
SUMMER
WINTER
SUMMER
Day of year (2008)
NORTH HEMISPHERE
SUMMER
Day of year (2008)
WINTER
SMS Dev V(%)
Kuwait Dev (%)
Day of year (2008)
WINTER
SUMMER
WINTER
Day of year (2008)
SOUTH HEMISPHERE
SUMMER
Trailing moving average (TMA)
Removing spurious diurnal variation
t
ri , j (t ) 
 I i , j (t )
t  23
24
TMA of the reference directional channel
(i=1) of the reference station (j=1)
Uncorrected data
Corrected data
Station
Directional Channel
(following Kuwabara et al., 2004; Okazaki et al., 2008)
10
Pitch angle calculation
 i , j (t )  i , j (t )   (t )
 i , j (t )
 (t )
i , j (t )
SUN
Pitch angle
 i , j  0
IMF direction
Asymptotic direction of view of
the i-th directional channel of
the j-th station
EARTH
 i , j  180
11
First order anisotropy
J i0 (t )  J 1 (t ) cos( i , j (t ))  J iobs
, j (t )
i є [1,4] (detector)
j є [1,13] (directional channel)
Nagoya
(i=1, j=1,2,…,13)
1 0 0 0 cos 𝜒1,1 (𝑡)
⋮
⋮ ⋮ ⋮ ⋮
1 0 0 0 cos 𝜒1,13 (𝑡)
São Martinho
(i=2, j=1,2,…,13
0 1 0 0 cos 𝜒2,1 (𝑡)
⋮
⋮ ⋮ ⋮ ⋮
0 1 0 0 cos 𝜒2,13 (𝑡)
Kuwait
(i=3, j=1,2,…,13
0 0 1 0 cos 𝜒3,1 (𝑡)
⋮
⋮ ⋮ ⋮ ⋮
0 0 1 0 cos 𝜒3,13 (𝑡)
Hobart
(i=4, j=1,2,…,13
0 0 0 1 cos 𝜒4,1 (𝑡)
⋮
⋮ ⋮ ⋮ ⋮
0 0 0 1 cos 𝜒4,13 (𝑡)
52x5
𝑜𝑏𝑠
𝐽1,1
(𝑡)
⋮
𝑜𝑏𝑠
𝐽1,13 (𝑡)
𝐽10 (t)
𝐽20 (𝑡)
𝐽30 (𝑡)
𝐽40 (𝑡)
𝐽1 (𝑡)
5x1

𝑜𝑏𝑠
𝐽2,1
(𝑡)
⋮
𝑜𝑏𝑠
𝐽2,13 (𝑡)
𝑜𝑏𝑠
𝐽3,1
(𝑡)
⋮
𝑜𝑏𝑠
𝐽3,13 (𝑡)
𝑜𝑏𝑠
𝐽4,1
(𝑡)
⋮
𝑜𝑏𝑠
𝐽4,13
(𝑡)
obs
0
J ical
(
t
)

J
(
t
)

J
,j
i, j
i (t )
52x1
𝑜𝑏𝑠
𝐽𝑖,𝑗
: observed normalized
deviation
J i0 (t ) : effects common for
all directional
channels but
different from one
station to the other
J 1 (t ): first-order anisotropy
 i , j (t ): pitch angle (deg)
Results
Systematic decrease for small pitch angles: loss cone signature!
SSC: 2011/11/24 23h51min
0.3%
Increase
Decrease
The diameter is proportional to the magnitude.
Results
Average Average Average
deviation deviation deviation
(%)
(%)
(%)
Average
deviation
(%)
Average deviation (%) for all directional channels in 10-degree pitch angle
regions in 5-hour periods in November 24th 2008.
16-21 h before
the SSC
11-16 h before
the SSC
6-11 h before
the SSC
1-6 h before the
SSC
Summary and conclusions
• This work illustrates a methodology for visualization of loss cones
signatures
• We used simultaneous observation of 4 multidirectional muon
detectors;
• Total number of directional channels: 60;
• Pressure and temperature effect were removed;
• Daily variation was removed by using a trailing moving average;
• Weak geomagnetic storm: the most difficult case to show the
precursors.
Acknowledgements
This work was partially founded by FAPESP under project number 2008-08840-0, by CNPq under
projects 303798/2008-4 and 481368/2010-8. Thanks to CAPES through the Graduate Program in
Space Geophysics. Radiosonde data has been provided by UKMO and BADC. Dst index data were
provided by the World Data Center for Geomagnetism, IMF and plasma data by the ACE mission
and Kp and SSC data by the Helmholtz Centre Potsdam German Research Centre for Geosciences.
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