Abstract
The geomagnetic storm of November 1998 is a unique event where IMF-Bz remained southward with values exceeding –15 nT for more than a day. The SYM/H index decreased from about 07 hr on 13 November 1998 reaching a minimum of about –120 nT around midnight of 13–14 November 1998. Features of the equatorial electrojet in the Indian region are studied during the geomagnetic storm event of 13–14 November 1998, based on the geomagnetic data from the chain of observatories in India. Sudden northward turning of IMF-Bz for a very short duration around 08 hr on 13 November 1998 resulted in a small and very short duration counter electrojet. A strong (–50 nT) and a long duration counter electrojet, right from 08 to 13 hr on 14 November 1998 was observed resulting in the absence of equatorial Es at Thumba. Absence of the equatorial ionization anomaly was also observed as seen from the ionograms over Thumba and ionspheric data from Ahmedabad. The delayed effect on 14 November 1998 is due to the disturbance dynamo effect.
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Acknowledgements
Thanks are due to Indian National Science Academy, New Delhi for providing Honorary Professorship to one of the authors (RGR) and to the Director, Physical Research Laboratory, Ahmedabad for the facilities provided to the authors (RGR and HC). Thanks are also due to J H King and Papitashwlli at Adnet System NASA GSFC and C D Aweb for the solar wind data, Space Physics Interactive Data Resources (SPIDR) Boulder, USA, World Data Centre for Geomagnetism Kyoto, Japan, Indian Institute of Geomagnetism, Navi Mumbai, India and Space Physics Laboratory, Thiruvananthapram, India. Thanks are also due to Rahul Shah for technical assistance.
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CHANDRA, H., RASTOGI, R.G., CHOUDHARY, R.K. et al. Equatorial electrojet in the Indian region during the geomagnetic storm of 13–14 November 1998. J Earth Syst Sci 125, 669–675 (2016). https://doi.org/10.1007/s12040-016-0683-0
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DOI: https://doi.org/10.1007/s12040-016-0683-0