Abstract
We examine the global ionospheric current in relation to X9.33 disk and X8.28 limb flares, which had significant differences in their solar X-ray and extreme ultraviolet (EUV) fluxes using the ground-based magnetometer data. At the peak of X9.33 flare, when X-ray and EUV radiations were significantly enhanced, the northern current vortex was situated at (40°N, 12 LT), while the southern current vortex was found at (30°S, 13LT). In comparison to the X8.28 flare, the northern current vortex was seen at (16°N, 12LT), while the southern current vortex was situated at (35°S, 14LT), which was 2 hr earlier in local time compared to those observed in the X9.33 flare. The changes in the total current intensity of the X9.33 flare is about 16% less than that of the X8.28 flare, thus revealing that the current variations relative to both flares are due to solar flux and universal time variations. The daytime X9.33 flare northern current vortex is stronger, while the southern vortex is less intense than the corresponding vortex of X8.28 flare. Even though both flares happened in equinox, the current vortices are nearly symmetric. There were significant hemispheric changes in the focus position leading to the hemispheric asymmetry. Our results indicated that both the enhanced X-ray and EUV fluxes during flares could have impacts on the ionospheric electric field and current, but their relative contributions and the underlying physics need further investigations.
| Original language | English |
|---|---|
| Article number | e2020SW002608 |
| Journal | Space Weather |
| Volume | 18 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - Nov 2020 |
All Science Journal Classification (ASJC) codes
- Atmospheric Science
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In: Space Weather, Vol. 18, No. 11, e2020SW002608, 11.2020.
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TY - JOUR
T1 - Ionospheric Current Variations Induced by the Solar Flares of 6 and 10 September 2017
AU - Owolabi, Charles
AU - Lei, Jiuhou
AU - Bolaji, O. S.
AU - Ren, Dexin
AU - Yoshikawa, Akimasa
N1 - Funding Information: This work was supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (XDB41000000), the National Natural Science Foundation of China (41831070 and 41974181), and the Open Research Project of Large Research Infrastructures of CAS—“Study on the interaction between low/middle latitude atmosphere and ionosphere based on the Chinese Meridian Project.” C. Owolabi would like to thank the Chinese Scholarship Council (CSC) for providing a CSC scholarship with which his doctoral program was undertaken. We acknowledge the use of data from the Chinese Meridian Project. The Chinese Meridian Project is a ground-based program to monitor China’s geospace environment to acknowledge the needs of both basic science and useful space weather operations (https://data.meridianproject.ac.cn/). For the ground magnetometer data we gratefully acknowledge the following: INTERMAGNET, Alan Thomson; CARISMA, PI Ian Mann; CANMOS, Geomagnetism Unit of the Geological Survey of Canada; The S-RAMP Database, PI K. Yumoto and Dr. K. Shiokawa; The SPIDR database; AARI, PI Oleg Troshichev; The MACCS program, PI M. Engebretson; GIMA; MEASURE, UCLA IGPP and Florida Institute of Technology; SAMBA, PI Eftyhia Zesta; 210 Chain, PI K. Yumoto; SAMNET, PI Farideh Honary; IMAGE, PI Liisa Juusola; Finnish Meteorological Institute, PI Liisa Juusola; Sodankylä Geophysical Observatory, PI Tero Raita; UiT the Arctic University of Norway, Tromsø Geophysical Observatory, PI Magnar G. Johnsen; GFZ German Research Centre For Geosciences, PI Jürgen Matzka; Institute of Geophysics, Polish Academy of Sciences, PI Anne Neska and Jan Reda; Polar Geophysical Institute, PI Alexander Yahnin and Yarolav Sakharov; Geological Survey of Sweden, PI Gerhard Schwarz; Swedish Institute of Space Physics, PI Masatoshi Yamauchi; AUTUMN, PI Martin Connors; DTU Space, Thom Edwards and PI Anna Willer; South Pole and McMurdo Magnetometer, PIs Louis J. Lanzarotti and Alan T. Weatherwax; ICESTAR; RAPIDMAG; British Artarctic Survey; McMac, PI Dr. Peter Chi; BGS, PI Dr. Susan Macmillan; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN); MFGI, PI B. Heilig; Institute of Geophysics, Polish Academy of Sciences, PI Anne Neska and Jan Reda; University of L'Aquila, PI M. Vellante; BCMT, V. Lesur and A. Chambodut; data obtained in cooperation with Geoscience Australia, PI Andrew Lewis; AALPIP, co-PIs Bob Clauer and Michael Hartinger; SuperMAG (http://supermag.jhuapl.edu/), PI Jesper W. Gjerloev; and data obtained in cooperation with the Australian Bureau of Meteorology, PI Richard Marshall. We thank the World Data Centre (WDC) for geomagnetism, Edinburgh (http://www.wdc.bgs.ac.uk/), Embrace MagNet (http://www.inpe.br/), Russian-Ukrainian Geomagnetic Data Center (RUGDC) operated by the Geophysical Center of the Russian Academy of Sciences (GCRAS; http://geomag.gcras.ru/), Low-Latitude Ionospheric Sensor Network (LISN; http://lisn.igp.gob.pe/data/) teams for providing geomagnetic field records. LISN is a project led by the University of Texas at Dallas in collaboration with the Geophysical Institute of Peru and other institutions that provide the record of geomagnetic field for research purpose. We thank the CDAWeb team (https://cdaweb.sci.gsfc.nasa.gov/) for providing ACE solar wind data and Space Physics Data Facility/Goddard Space Flight Center OMNIWeb Interface (https://omniweb.gsfc.nasa.gov/) for providing AE, SYM-H, F10.7 solar radio flux, and Kp indices used in this study. The authors acknowledge GOES-15 (https://satdat.ngdc.noaa.gov/) and SDO (http://lasp.colorado.edu/eve/data_access/) teams for providing solar X-ray and EUV fluxes data. Funding Information: This work was supported by the B‐type Strategic Priority Program of the Chinese Academy of Sciences (XDB41000000), the National Natural Science Foundation of China (41831070 and 41974181), and the Open Research Project of Large Research Infrastructures of CAS—“Study on the interaction between low/middle latitude atmosphere and ionosphere based on the Chinese Meridian Project.” C. Owolabi would like to thank the Chinese Scholarship Council (CSC) for providing a CSC scholarship with which his doctoral program was undertaken. We acknowledge the use of data from the Chinese Meridian Project. The Chinese Meridian Project is a ground‐based program to monitor China’s geospace environment to acknowledge the needs of both basic science and useful space weather operations ( https://data.meridianproject.ac.cn/ ). For the ground magnetometer data we gratefully acknowledge the following: INTERMAGNET, Alan Thomson; CARISMA, PI Ian Mann; CANMOS, Geomagnetism Unit of the Geological Survey of Canada; The S‐RAMP Database, PI K. Yumoto and Dr. K. Shiokawa; The SPIDR database; AARI, PI Oleg Troshichev; The MACCS program, PI M. Engebretson; GIMA; MEASURE, UCLA IGPP and Florida Institute of Technology; SAMBA, PI Eftyhia Zesta; 210 Chain, PI K. Yumoto; SAMNET, PI Farideh Honary; IMAGE, PI Liisa Juusola; Finnish Meteorological Institute, PI Liisa Juusola; Sodankylä Geophysical Observatory, PI Tero Raita; UiT the Arctic University of Norway, Tromsø Geophysical Observatory, PI Magnar G. Johnsen; GFZ German Research Centre For Geosciences, PI Jürgen Matzka; Institute of Geophysics, Polish Academy of Sciences, PI Anne Neska and Jan Reda; Polar Geophysical Institute, PI Alexander Yahnin and Yarolav Sakharov; Geological Survey of Sweden, PI Gerhard Schwarz; Swedish Institute of Space Physics, PI Masatoshi Yamauchi; AUTUMN, PI Martin Connors; DTU Space, Thom Edwards and PI Anna Willer; South Pole and McMurdo Magnetometer, PIs Louis J. Lanzarotti and Alan T. Weatherwax; ICESTAR; RAPIDMAG; British Artarctic Survey; McMac, PI Dr. Peter Chi; BGS, PI Dr. Susan Macmillan; Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN); MFGI, PI B. Heilig; Institute of Geophysics, Polish Academy of Sciences, PI Anne Neska and Jan Reda; University of L'Aquila, PI M. Vellante; BCMT, V. Lesur and A. Chambodut; data obtained in cooperation with Geoscience Australia, PI Andrew Lewis; AALPIP, co‐PIs Bob Clauer and Michael Hartinger; SuperMAG ( http://supermag.jhuapl.edu/ ), PI Jesper W. Gjerloev; and data obtained in cooperation with the Australian Bureau of Meteorology, PI Richard Marshall. We thank the World Data Centre (WDC) for geomagnetism, Edinburgh ( http://www.wdc.bgs.ac.uk/ ), Embrace MagNet ( http://www.inpe.br/ ), Russian‐Ukrainian Geomagnetic Data Center (RUGDC) operated by the Geophysical Center of the Russian Academy of Sciences (GCRAS; http://geomag.gcras.ru/ ), Low‐Latitude Ionospheric Sensor Network (LISN; http://lisn.igp.gob.pe/data/ ) teams for providing geomagnetic field records. LISN is a project led by the University of Texas at Dallas in collaboration with the Geophysical Institute of Peru and other institutions that provide the record of geomagnetic field for research purpose. We thank the CDAWeb team ( https://cdaweb.sci.gsfc.nasa.gov/ ) for providing ACE solar wind data and Space Physics Data Facility/Goddard Space Flight Center OMNIWeb Interface ( https://omniweb.gsfc.nasa.gov/ ) for providing , ‐, solar radio flux, and indices used in this study. The authors acknowledge GOES‐15 ( https://satdat.ngdc.noaa.gov/ ) and SDO ( http://lasp.colorado.edu/eve/data_access/ ) teams for providing solar X‐ray and EUV fluxes data. AE SYM H F 10.7 Kp Publisher Copyright: ©2020. The Authors.
PY - 2020/11
Y1 - 2020/11
N2 - We examine the global ionospheric current in relation to X9.33 disk and X8.28 limb flares, which had significant differences in their solar X-ray and extreme ultraviolet (EUV) fluxes using the ground-based magnetometer data. At the peak of X9.33 flare, when X-ray and EUV radiations were significantly enhanced, the northern current vortex was situated at (40°N, 12 LT), while the southern current vortex was found at (30°S, 13LT). In comparison to the X8.28 flare, the northern current vortex was seen at (16°N, 12LT), while the southern current vortex was situated at (35°S, 14LT), which was 2 hr earlier in local time compared to those observed in the X9.33 flare. The changes in the total current intensity of the X9.33 flare is about 16% less than that of the X8.28 flare, thus revealing that the current variations relative to both flares are due to solar flux and universal time variations. The daytime X9.33 flare northern current vortex is stronger, while the southern vortex is less intense than the corresponding vortex of X8.28 flare. Even though both flares happened in equinox, the current vortices are nearly symmetric. There were significant hemispheric changes in the focus position leading to the hemispheric asymmetry. Our results indicated that both the enhanced X-ray and EUV fluxes during flares could have impacts on the ionospheric electric field and current, but their relative contributions and the underlying physics need further investigations.
AB - We examine the global ionospheric current in relation to X9.33 disk and X8.28 limb flares, which had significant differences in their solar X-ray and extreme ultraviolet (EUV) fluxes using the ground-based magnetometer data. At the peak of X9.33 flare, when X-ray and EUV radiations were significantly enhanced, the northern current vortex was situated at (40°N, 12 LT), while the southern current vortex was found at (30°S, 13LT). In comparison to the X8.28 flare, the northern current vortex was seen at (16°N, 12LT), while the southern current vortex was situated at (35°S, 14LT), which was 2 hr earlier in local time compared to those observed in the X9.33 flare. The changes in the total current intensity of the X9.33 flare is about 16% less than that of the X8.28 flare, thus revealing that the current variations relative to both flares are due to solar flux and universal time variations. The daytime X9.33 flare northern current vortex is stronger, while the southern vortex is less intense than the corresponding vortex of X8.28 flare. Even though both flares happened in equinox, the current vortices are nearly symmetric. There were significant hemispheric changes in the focus position leading to the hemispheric asymmetry. Our results indicated that both the enhanced X-ray and EUV fluxes during flares could have impacts on the ionospheric electric field and current, but their relative contributions and the underlying physics need further investigations.
UR - http://www.scopus.com/inward/record.url?scp=85096430056&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85096430056&partnerID=8YFLogxK
U2 - 10.1029/2020SW002608
DO - 10.1029/2020SW002608
M3 - Article
AN - SCOPUS:85096430056
SN - 1542-7390
VL - 18
JO - Space Weather
JF - Space Weather
IS - 11
M1 - e2020SW002608
ER -