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Investigation of Pc5 pulsations effects and magnetospheric processes during intense geomagnetic storms
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  • Sarup Khadka Saurav Saurav,
  • Monika Karki,
  • Binod Adhikari,
  • Ashok Silwal,
  • Luciano Aparecido Magrini,
  • Ezequiel Echer,
  • Odim Mendes,
  • Margarete Oliveira Domingues,
  • Sujan Prasad Gautam
Sarup Khadka Saurav Saurav
Patan Multiple college, Tribhuvan University
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Monika Karki
Amrit Campus, Tribhuvan University
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Binod Adhikari
St.Xavier's College, ,Maitighar

Corresponding Author:binod.adhi@gmail.com

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Ashok Silwal
Patan Multiple Campus, Tribhuvan University
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Luciano Aparecido Magrini
1Federal Institute of Education, Science and Technology of São Paulo (IFSP),
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Ezequiel Echer
National Institute for Space Research (INPE)
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Odim Mendes
National Institute for Space Research (INPE)
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Margarete Oliveira Domingues
National Institute for Space Research (INPE)
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Sujan Prasad Gautam
Central Department of Physics, Tribhuvan University
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Abstract

Giant pulsations belonging to the Pc5 frequency band were conceived by Rolf (1931). Such pulsations are influenced by magnetospheric processes produced by the solar wind. The purpose of this study is to investigate the Pc5 ULF waves and their relationship to solar parameters and geomagnetic indices, respectively, utilizing data from ground-based magnetometers and data provided by Operating Mission as Nodes on the Internet (OMNI). Magnetic observatories over Earth’s surface reported intense long-period ULF activity on 19 28 February 2014 and 22-23 June 2015. We discovered a highly significant correlation between global Pc5 ULF waves and other interplanetary parameters, as well as a clear peak-to-peak correspondence during storms. We performed continuous wavelet transform (CWT) on the Pc5 integrated power (Ipow) and discovered that the majority of the intense Pc5 spectra are localized within the 64-256 minute Fourier period band. Our results suggest that geomagnetic fluctuations observed at low latitudes do not originate locally but rather are a reflection of global geomagnetic field variations with primary sources in the magnetosphere and high latitude ionosphere, which is consistent with the study of Gupta (1976). We discovered only nominal effects of IMF Bz on Pc5 pulsations, despite its southern counterpart being widely believed to be the principal driver of geomagnetic storms. Additionally, we discovered a moderate effect of solar wind pressure on Pc5 pulsations. A cross-correlation study, on the other hand, indicated a strong and positive association between Pc5 pulsations and solar wind velocity without lag for both geomagnetic activities.