Role of IMF By in the prompt electric field disturbances over equatorial ionosphere during a space weather event
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- Physical Research Lab., Ahmedabad (India)
- Indian Inst. of Geomagnetism, Navi Mumbai (India)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); New Mexico Consortium, Los Alamos, NM (United States)
- Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Bradley Dept. of Electrical and Computer Engineering
On 7 January 2005 (Ap=40) prompt penetration electric field perturbations of opposite polarities were observed over Thumba and Jicamarca on a few occasions during 13:45–16:30 UT. However, the electric field was found to be eastward during 14:45–15:30 UT over both Thumba and Jicamarca contrary to the general expectation wherein opposite polarities are expected at nearly antipodal points. On closer scrutiny, three important observational features are noticed during 14:10–15:15 UT. First, during 14:10–14:45 UT, despite increasing southward interplanetary magnetic field (IMF) Bz condition, the already westward electric field over Thumba weakened (less westward) while the eastward electric field over Jicamarca intensified (more eastward). Second, the electric field not only became anomalously eastward over Thumba but also got intensified further during 14:45–15:00 UT similar to Jicamarca. Third, during 15:00–15:15 UT, despite IMF Bz remaining steadily southward, the eastward electric field continued to intensify over Thumba but weakened over Jicamarca. It is suggested that the changes in IMF By component under southward IMF Bz condition are responsible for skewing the ionospheric equipotential patterns over the dip equator in such a way that Thumba came into the same DP2 cell as that of Jicamarca leading to anomalous electric field variations. Magnetic field measurements along the Indian and Jicamarca longitude sectors and changes in high-latitude ionospheric convection patterns provide credence to this proposition. Therefore, in conclusion, the present investigation shows that the variations in IMF By are fundamentally important to understand the prompt penetration effects over low latitudes.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); USDOE; Department of Space, Government of India
- Grant/Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1402608
- Report Number(s):
- LA-UR-16-22089; TRN: US1703006
- Journal Information:
- Journal of Geophysical Research. Space Physics, Vol. 122, Issue 2; ISSN 2169-9380
- Publisher:
- American Geophysical UnionCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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