PEM12-01

会場:101A

時間:5 月 26 日 14:15-14:30

Ionizing effects of magnetospheric electrons in the low-latitude ionosphere during recurrent magnetic storms
Ionizing effects of magnetospheric electrons in the low-latitude ionosphere during recurrent magnetic storms
SUVOROVA, Alla1∗ ; HUANG, Chien M.1
SUVOROVA, Alla1∗ ; HUANG, Chien M.1
1
1

Institute of Space Science, National Central University
Institute of Space Science, National Central University

The general concept of the near-Earth radiation asserts that fluxes of energetic electrons in the equatorial ionosphere and outside the region of South Atlantic Anomaly are stably tenuous and negligible due to permanent effective scattering and losing
energy in interaction with atmospheric neutrals. In literature, this region is called a forbidden zone because it locates below theinner allowed Störmer zone or inner radiation belt. Radiation monitoring by a fleet of the NOAA satellites in low-Earth orbit
have revealed significant enhancements of energetic electrons in the forbidden zone during enhanced substorm activity and geomagnetic storms. A regular occurrence of the enhanced forbidden energetic electrons (FEE) in the solar cycles 23 and 24 relates
closely to recurrent magnetic storms. Superposed epoch analysis shows high probability of the FEE enhancement occurrence
during first three days of a recurrent storm. Due to ionizing effect, the FEE enhancements contribute significantly to ionosphericpositive phase during recurrent geomagnetic storms.
キーワード: magnetosphere-ionosphere coupling, recurrent magnetic storms, forbidden electron enhancements, positive ionospheric storms
Keywords: magnetosphere-ionosphere coupling, recurrent magnetic storms, forbidden electron enhancements, positive ionospheric storms

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PEM12-02

会場:101A

時間:5 月 26 日 14:30-14:45

Recurrent ionospheric storms during solar minimum
Recurrent ionospheric storms during solar minimum
DMITRIEV, Alexei1∗
DMITRIEV, Alexei1∗
1Institute of Space Science, National Central University, Chung-Li, Taiwan, 2 Skobeltsyn Institute of Nuclear Physics Moscow
State University, Moscow, Russia
1
Institute of Space Science, National Central University, Chung-Li, Taiwan, 2 Skobeltsyn Institute of Nuclear Physics Moscow
State University, Moscow, Russia
Ionospheric storms related to geomagnetic disturbances are a subject of great scientific interest. We present a comprehensive
analysis of perturbations in the low- and mid-latitude ionosphere during moderate recurrent geomagnetic storms (RGSs) in
the solar minimum of 2007 - 2008. It is shown that during so-called recurrent ionospheric storms (RIS), the heliospheric magnetospheric - ionospheric - thermospheric coupling remains highly efficient even during solar minimum. Analysis of global
ionospheric maps of vertical total electron content (VTEC) derived on the base of GPS network showed that VTEC has a tendency
to decrease and negative ionospheric storms occur right before the onset and on the late recovery phase of RGS. A positive
ionospheric storm is developed on 2 to 4 day after the onset, i.e. on the recovery phase of RGS produced by high-intensity
long-duration continuous auroral activity. The ionospheric response reveals prominent longitudinal and local time variations.
Such effects as penetrating electric fields of interplanetary and magnetospheric origin, disturbance dynamo electric fields, neutral
winds and thermospheric chemical composition changes are considered as possible mechanisms responsible for the observed
recurrent ionospheric storms.
キーワード: ionospheric storms, recurrent geomagnetic storms, corotating interaction regions, high-speed solar wind
Keywords: ionospheric storms, recurrent geomagnetic storms, corotating interaction regions, high-speed solar wind

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