Precursor signatures of storm sudden commencement observed by a network of muon detectors

1. Precursor signatures of storm sudden commencement observed by a network of muon detectors C. R. BRAGA1, 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 2 Universidade 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 E-mail: crbraga@dge.inpe.br

2. Global Muon Detector Network (GMDN) 6 x 6 3 x 3 4 x 7 Nagoya 3 x 3 (4 x 4) Kuwait Hobart 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 São Martinho da Serra

4. Source: Yashin et al. (2006).

5. 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.

6. Negative temperature effect Dev(%)=-5.9 (%/km) ∙ ∆H (km) + 97% Correlation=-0.95 ∆H: deviation of the altitude of 100 hPa Deviation Na V(%) Altitude (km) of 100 hPa layer

7. Temperature effect correction Dev(%)=-5.9 (%/km) ∙ ∆H (km) + 97% 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 Correlation=-0.95 Deviation Na V(%) β: regression coefficient (slope) α: correlation coefficient Altitude (km) of 100 hPa layer

8. High-altitude measurements sites

9. Seasonal temperature effect correction Nagoya Dev V(%) Hobart Dev V(%) WINTER SUMMER WINTER SUMMER WINTER SUMMER Day of year (2008) Day of year (2008) SMS Dev V(%) Kuwait Dev (%) WINTER SUMMER WINTER SUMMER WINTER SUMMER Day of year (2008) Day of year (2008) NORTH HEMISPHERE SOUTH HEMISPHERE

10. Trailing moving average (TMA) Removing spurious diurnal variation TMA of the reference directional channel (i=1) of the reference station (j=1) Uncorrected data Station Directional Channel Corrected data (following Kuwabara et al., 2004; Okazaki et al., 2008)

11. Pitch angle calculation SUN B Pitch angle IMF direction Asymptotic direction of view of the i-th directional channel of the j-th station EARTH

12. First order anisotropy i є [1,4] (detector) j є [1,13] (directional channel) Nagoya (i=1, j=1,2,…,13) : observed normalized deviation : effects common for all directional channels but different from one station to the other São Martinho (i=2, j=1,2,…,13 Kuwait (i=3, j=1,2,…,13 : first-order anisotropy 5x1 Hobart (i=4, j=1,2,…,13 : pitch angle (deg) 52x5 52x1

13. 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.

14. Results Average deviation (%) for all directional channels in 10-degree pitch angle regions in 5-hour periods in November 24th 2008. Average deviation (%) 16-21 h before the SSC Average deviation (%) 11-16 h before the SSC Average deviation (%) 6-11 h before the SSC Average deviation (%) 1-6 h before the SSC

15. 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.

16. Thank you! 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. References [1] T. Kuwabara et al., 2006, Space Weather, 4, S08001 [2] D. Ruffolo et al., 1999, Proceedings of the 26th Int. Cosmic Ray Conf., 53. [3] L. I. Dorman: 1963 Geophysical and Astrophysical Aspects of Cosmic Rays, Prog. Phys., Cosmic Ray Elementary Particles, North-Holland. [4] K. Nagashima et al., 1992, Planet. Space Sci., 40: 1109-1137 [5] K. Munakata et al., 2000, J. Geophys. Res., 105 (A12): 27427-27468 [6] K. Kudela; M. Storini, 2006, Adv. Space Res., 37(8): 1443-1449 [7] A. V. Belov et al., 2001, Proceedings of the 27th Int. Cosmic Ray Conf., 3507-3510 [8] Y. Okazaki et al., 2008, Astrophys. J., 681: 693-707 [9] A. Duperier, 1944, Terrestrial and Magnetic Atmospheric Electricity, 49: 1-7 [10] A. Duperier, 1949, Proceddings of the Physical Society, 62: 684-696 [11] P. M. S. Blackett, 1938, Phys. Rev. Let. 54: 973-974 [12] S. Sagisaka, 1986, Il Nuovo Cimento, 9C: 4809 [13] T. Kuwabara et al., 2004, J. Geophys. Res., 100: L19803.