precursor signatures of storm sudden commencement observed by a network of muon detectors c. r....
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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, Brazil2 Universidade do Vale do Paraíba ,São Jose dos Campos, Brazil3 Southern Regional Space Research Center, Santa Maria, Brazil
4 Physics Department, Shinshu University, Matsumoto, Japan5 Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, USA
6 Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan7 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
E-mail: [email protected]
2Detectors photographs (except Sao Martinho da Serra): private communication with Prof. K. Munakata, 2010 and Prof. I. Sabbah, 2011Background source: http://earthsatellitemaps.com/wp-content/uploads/2009/06/mapofearth.jpg, 2010
Global Muon Detector Network (GMDN)
São Martinho da Serra
Kuwait
Hobart
Nagoya
4 x 7
6 x 6
3 x 3 (4 x 4)
3 x 3
Methodology
- Pressure effect correction;- Temperature effect correction;- Trailing moving average;- First order anisotropy;- Normalization by statistical error.
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.
Negative temperature effect
ΔHβN=ΔN TT
TEDNOTCORRECTCORRECTEDETEMPERATUR ΔNN=N _
∆H: deviation of the altitude of 100 hPa
Correlation=-0.95
Dev(%)=-5.9 (%/km) ∆H (km) + 97%∙
Dev
iatio
n N
a V(
%)
Altitude (km) of 100 hPa layer
Temperature effect correction
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
Dev(%)=-5.9 (%/km) ∆H (km) + 97%∙
Dev
iatio
n N
a V(
%)
Altitude (km) of 100 hPa layer β: regression coefficient (slope)α: correlation coefficient
High-altitude measurements sites
High-altitude pressure measurements sites
Muon stationApprox. distance
(km)NameGeographic coordinates
(degrees)
Shionomisaki 33.5 N; 140.1 E
Nagoya
200
Tateno 36.0 N;140.1 E 400
Wajina 37.4 N; 136.9 E 300
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
Day of year (2008)
Day of year (2008) Day of year (2008)
Day of year (2008)
Seasonal temperature effect correctionKu
wai
t Dev
(%)
Nag
oya
Dev
V(%
)
Hob
art D
ev V
(%)
SMS
Dev
V(%
)
NORTH HEMISPHERE SOUTH HEMISPHERE
SUMMERWINTER WINTER
SUMMERWINTER WINTER
SUMMER
SUMMER
SUMMER
SUMMER WINTER
WINTER
Trailing moving average (TMA)
24
)()(
,23
,
tItr
ji
t
tji
TMA of the reference directional channel (i=1) of the reference station (j=1)
Uncorrected data
Corrected data Directional ChannelStation
10
Removing spurious diurnal variation
(following Kuwabara et al., 2004; Okazaki et al., 2008)
Pitch angle calculation
)()()( ,, ttt jiji
)(, tji
)(, tji
)(tPitch angle
IMF direction
SUNSUN
B
0, ji
180, ji
Asymptotic direction of view of the i-th directional channel of the j-th station
EARTH
11
First order anisotropy
1⋮1 0⋮0 0⋮0 0⋮0 cos𝜒1,1(𝑡)⋮cos𝜒1,13(𝑡)
0⋮0 1⋮1 0⋮0 0⋮0 cos𝜒2,1 (𝑡)⋮cos𝜒2,13(𝑡)
0⋮0 0⋮0 1⋮1 0⋮0 cos𝜒3,1(𝑡)⋮cos𝜒3,13(𝑡)
0⋮0 0⋮0 0⋮0 1⋮1 cos𝜒4,1(𝑡)⋮cos𝜒4,13(𝑡)
𝐽1,1𝑜𝑏𝑠(𝑡)⋮𝐽1,13𝑜𝑏𝑠(𝑡)
𝐽2,1𝑜𝑏𝑠(𝑡)⋮𝐽2,13𝑜𝑏𝑠 (𝑡)
𝐽3,1𝑜𝑏𝑠(𝑡)⋮𝐽3,13𝑜𝑏𝑠 (𝑡)
𝐽4,1𝑜𝑏𝑠(𝑡)⋮𝐽4,13𝑜𝑏𝑠 (𝑡)
𝐽10(t)
𝐽20(𝑡)
𝐽30(𝑡)
𝐽40(𝑡)
𝐽 1(𝑡)
Nagoya(i=1, j=1,2,…,13)
𝐽𝑖,𝑗𝑜𝑏𝑠
São Martinho(i=2, j=1,2,…,13
Kuwait(i=3, j=1,2,…,13
Hobart(i=4, j=1,2,…,13
52x152x5
5x1
: observed normalized deviation
)())(cos()()( ,,10 tJttJtJ obs
jijii i є [1,4] (detector)
j є [1,13] (directional channel)
)()()( 0,, tJtJtJ iobsji
calji
)(0 tJ i
)(1 tJ
: effects common for all directional channels but
different from one station to the other
: first-order anisotropy
: pitch angle (deg))(, tji
ResultsSystematic decrease for small pitch angles: loss cone signature!
The diameter is proportional to the magnitude.
Increase Decrease
SSC: 2011/11/24 23h51min
0.3%
Aver
age
devi
ation
(%
)
Aver
age
devi
ation
(%
)
Aver
age
devi
ation
(%
)
Aver
age
devi
ation
(%
)
Results
1-6 h before the SSC
6-11 h before the SSC
11-16 h before the SSC
16-21 h before the SSC
Average deviation (%) for all directional channels in 10-degree pitch angle regions in 5-hour periods in November 24th 2008.
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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Thank you!