12-20 July 2017
BEXCO
Asia/Seoul timezone
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Contribution

BEXCO - Room B(103/104/105)

[CRI274] Effects of atmospheric electric field on muon intensity observed in GRAPES-3 experiment

Speakers

  • Balakrishnan HARIHARAN

Primary authors

  • B. HARIHARAN (Tata Institute of Fundamental Research, India)

Co-authors

  • S.K. GUPTA (Tata Institute of Fundamental Research, India)
  • S.R. DUGAD (Tata Institute of Fundamental Research, India)
  • Y. HAYASHI (Graduate School of Science, Osaka City University, Japan)
  • S. KAWAKAMI (Graduate School of Science, Osaka City University, Japan)
  • P. JAGADEESAN (Tata Institute of Fundamental Research, India)
  • P.K. MOHANTY (Tata Institute of Fundamental Research, India)
  • A. JAIN (Tata Institute of Fundamental Research, India)
  • B.S. RAO (Tata Institute of Fundamental Research, India)
  • P.K. NAYAK (Tata Institute of Fundamental Research, India)

Description

During bad weather conditions, muon flux above 1 GeV observed in GRAPES-3 muon telescope shows large variations. The atmospheric electric field is believed to be responsible for acceleration of cosmic ray muons. A thunderstorm event observed on 30 September 2015 is discussed here. The field of view of large area (560 m^2) tracking muon telescope at GRAPES-3 allows study of muon intensity variations in 169 directions with ∼4◦ resolution. This event shows large decrease in North-East directions, with a maximum decrease of -0.6 % in all directions combined and -4.5 % in a single direction. Muons from selected directions were combined and processed with fast Fourier transform (FFT) to remove slow and ultra-fast variations (△f = 10-200 cpd). The filtered data shows maximum decrease of -1.2 % with statistical significance of 9σ. Monte Carlo simulations were carried out with modified CORSIKA package to incorporate electric field. Simulations show that electric potential ∼1 GV is needed to get variation of 1 % in GRAPES-3 muon flux.