Storm‐Enhanced Development of Postsunset Equatorial Plasma Bubbles Around the Meridian 120°E/60°W on 7–8 September 2017

Storm time development of equatorial plasma bubbles (EPBs) around the meridian 120°E/60°W during early September 2017, when the Bz component of interplanetary magnetic field (IMF) experienced two large southward excursions, producing a strong geomagnetic storm that included two main phase decreases,...

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Bibliographic Details
Published in:Journal of geophysical research. Space physics 2018-09, Vol.123 (9), p.7985-7998
Main Authors: Li, Guozhu, Ning, Baiqi, Wang, Chi, Abdu, M. A., Otsuka, Yuichi, Yamamoto, M., Wu, Jian, Chen, Jinsong
Format: Article
Language:English
Subjects:
Bubbles
Disturbance
disturbance electric field
Drift
Electric fields
equatorial plasma bubbles
Evolution
geomagnetic storm
Geomagnetic storms
Geomagnetism
international space weather meridian circle program
Interplanetary magnetic field
Ionosondes
Irregularities
Latitude
Magnetic fields
Magnetic storms
Navigation
Navigation satellites
Navigation systems
Penetration
Plasma bubbles
Polarity
Satellites
Space weather
Storms
Sunset
Weather
westward drifts
west‐tilted structure
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Summary:Storm time development of equatorial plasma bubbles (EPBs) around the meridian 120°E/60°W during early September 2017, when the Bz component of interplanetary magnetic field (IMF) experienced two large southward excursions, producing a strong geomagnetic storm that included two main phase decreases, was investigated. The observations from networks of Global Navigation Satellite Systems total electron content receivers, very high frequency radars, and ionosondes operated around the meridian reveal that in the American and Asian sectors, intense EPB irregularities developed and extended to dip latitudes of ~30°N and 46°N, respectively, following rapid sunset F layer height rises during two episodes of strong southward IMF Bz excursions. The storm‐enhanced EPB irregularities, however, were not observed following the sunset terminator in the Pacific sector, where the sunset rise of F layer was not detected. More interestingly, the EPBs in the Asian sector were observed to drift toward the west, with velocity increasing from ~30 m/s at low latitude to ~95 m/s at middle latitude. The poleward increasing westward drifts drove the formation of west‐titled structure of irregularities. For the EPBs in the American sector, no apparent west‐tilted structure was detected. The results indicate that the prompt penetration undershielding electric fields (PPEF) of eastward polarity resulting from the two IMF Bz southward excursions dominated the generation of postsunset EPBs in the American and Asian sectors, respectively. The westward drifts of PPEF‐induced EPBs in the Asian sector could be attributed dominantly to disturbance westward wind, with a possible contribution to it arising from the PPEF. Plain Language Summary The development and evolution of equatorial plasma bubbles (EPBs) exhibit complex global behavior during geomagnetic storms. In recent years, an international space weather meridian circle program, which aims to provide a global picture of unfolding space weather events by using diverse instruments along the approximate meridian 120°E/60°W, that is, the Asian and American longitude sectors, was launched. Considering the sunset interval (~12 hr) between the two longitudes, it is expected that the development of postsunset EPBs, if enhanced in one region by short‐lived prompt penetration electric fields (PPEF), would be inhibited in the other region under the delayed and long duration effect of disturbance dynamo electric fields. Here we report a unique cas
ISSN:2169-9380
2169-9402
DOI:10.1029/2018JA025871