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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Unusual Generation of Localized EPB in the Dawn Sector Triggered by a Moderate Geomagnetic Storm

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Author(s):
Sripathi, S. [1] ; Abdu, M. A. [2, 3] ; Patra, A. K. [4] ; Ghodpage, R. N. [5]
Total Authors: 4
Affiliation:
[1] Indian Inst Geomagnetism, New Bombay - India
[2] Inst Tecnol Aeronaut, Sao Jose Dos Campos - Brazil
[3] Inst Nacl Pesquisas Espaciais, Sao Jose Dos Campos - Brazil
[4] ISRO, DOS, Natl Atmospher Res Lab, Gadanki - India
[5] Shivaji Univ, Indian Inst Geomagnetism, MF Radar Ctr, Kolhapur, Maharashtra - India
Total Affiliations: 5
Document type: Journal article
Source: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS; v. 123, n. 11, p. 9697-9710, NOV 2018.
Web of Science Citations: 0
Abstract

An interesting piece of observation related to the equatorial plasma bubble (EPB) that is triggered by a geomagnetic storm at dawn sector on 4-5 February 2011 is presented. The storm activity was initiated at 17 UT when interplanetary magnetic field (IMF) Bz turned southward and the Dst index started decreasing (accompanied by AE intensifications) attaining its minimum at -70 nT. The IMF Bz presented large fluctuations marked by southward/northward transitions at slow and rapid rates and eventually returning to normal in the morning of 5 February. Observations from the very high frequency radar located at Gadanki, an off-equatorial station; an all-sky imager located at Kolhapur, a low-latitude station; and an ionosonde at Tirunelveli, an equatorial station, are analyzed to study the impact of this storm on the postmidnight to presunrise equatorial spread F. The results demonstrate that EPB irregularities can be generated by penetration electric field during what can be characterized as a moderate storm event. In contrast to prevailing belief, the present results show that EPB/equatorial spread F can be generated by undershielding electric field in the dawn sector, caused by an unusually delayed polarity reversal of the penetration electric field. The results further reveal oscillatory behavior in the height of F layer topside irregularities in association with IMF Bz oscillations. Observation of radar echoes from nighttime E layer irregularity structures and their Doppler velocities representing the penetration electric field polarity and intensity are also a notable finding of this paper. (AU)

FAPESP's process: 16/24970-7 - The Scintillation Prediction Observation Research Task (SPORT)
Grantee:Mangalathayil Ali Abdu
Support Opportunities: Research Projects - Thematic Grants