Cross-correlation and cross-wavelet analyses of the solar wind IMF &lt;i&gt;B&lt;/i&gt;&lt;sub&gt;&lt;i&gt;z&lt;/i&gt;&lt;/sub&gt; and auroral electrojet index AE coupling during HILDCAAs

Adriane Marques de Souza; Ezequiel Echer; Mauricio Bolzan; Rajkumar Hajra

doi:10.5194/angeo-36-205-2018

Cross-correlation and cross-wavelet analyses of the solar wind IMF Bz and auroral electrojet index AE coupling during HILDCAAs

Adriane Marques de Souza ¹ Ezequiel Echer ¹ Mauricio Bolzan ² Rajkumar Hajra ³

1 INPE - National Institute for Space Research

2 Federal University of Goiás [Jataí]

3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

Abstract : Solar-wind-geomagnetic activity coupling during high-intensity long-duration continuous AE (auroral electro-jet) activities (HILDCAAs) is investigated in this work. The 1 min AE index and the interplanetary magnetic field (IMF) B z component in the geocentric solar magnetospheric (GSM) coordinate system were used in this study. We have considered HILDCAA events occurring between 1995 and 2011. Cross-wavelet and cross-correlation analyses results show that the coupling between the solar wind and the magneto-sphere during HILDCAAs occurs mainly in the period ≤ 8 h. These periods are similar to the periods observed in the in-terplanetary Alfvén waves embedded in the high-speed solar wind streams (HSSs). This result is consistent with the fact that most of the HILDCAA events under present study are related to HSSs. Furthermore, the classical correlation analysis indicates that the correlation between IMF B z and AE may be classified as moderate (0.4-0.7) and that more than 80 % of the HILDCAAs exhibit a lag of 20-30 min between IMF B z and AE. This result corroborates with Tsurutani et al. (1990) where the lag was found to be close to 20-25 min. These results enable us to conclude that the main mechanism for solar-wind-magnetosphere coupling during HILDCAAs is the magnetic reconnection between the fluctuating, negative component of IMF B z and Earth's magnetopause fields at periods lower than 8 h and with a lag of about 20-30 min.

Keywords : Magnetospheric physics Solar wind-magnetosphere interactions

Type de document :

Article dans une revue

Annales Geophysicae, European Geosciences Union, 2018, 36 (1), pp.205-211. 〈10.5194/angeo-36-205-2018〉

Domaine :

Planète et Univers [physics] / Sciences de la Terre / Géophysique [physics.geo-ph]

Physique [physics] / Physique [physics] / Physique de l'espace [physics.space-ph]

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https://hal-insu.archives-ouvertes.fr/insu-01976498
Contributeur : Nathalie Pothier <>
Soumis le : jeudi 10 janvier 2019 - 10:05:58
Dernière modification le : jeudi 7 février 2019 - 17:10:13

angeo-36-205-2018.pdf

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Cross-correlation and cross-wavelet analyses of the solar wind IMF <i>B</i><sub><i>z</i></sub> and auroral electrojet index AE coupling during HILDCAAs

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