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The Structure of Current System for Polar Substorm. A.Kotikov, Saint-Petersburg University A.Zaitsev, IZMIRAN, e-mail: zaitsev@izmiran.ru.
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The Structure of Current Systemfor Polar Substorm A.Kotikov, Saint-Petersburg University A.Zaitsev, IZMIRAN, e-mail: zaitsev@izmiran.ru
Statistical current system based on IGY data – main sources are westward and eastward electrojets and currents in polar cap. A –convective, B – explosive,C – polar cap currentsD - complex current system Reference: Y.Feldstein, A.Zaitsev, Sd-variation of the magnetic field in high latitudes with different intensity of magnetic disturbances, Annales Geoph.,v.24, n.2, pp.1-8, 1968
Eastward Electrojet : Facts and Rumors Rumors: eastward electrojet does not exist as own source, does not play a significant role in substorm Facts: eastward electrojet is the essential source of polar . geomagnetic disturbances on his own, two types of eastward electrojets are observed Convective Explosive Positioned around 15-18 LT positioned around 21-00 LT Spread current sheet Distinctive jet-like current Strong seasonal dependence No seasonal dependence Have not accompany by riometer Accompanied by riometer absorption Have not pronounced conjugacy Clear conjugate Not display Harang discontinuity To form the Harang discontinuity Have a connection with magnetosphere Have a connection with the partial convection cell ? ring current ?
Extra strong eastward electrojet Magnetic Superstorm at Jan.11, 1997Cape Kamenny, Yamal, Siberia Harang discontinuity, South Pole station, 1977
Connection solar wind – magnetosphere – ionosphere currents Magnetometers of Prognoz-7, 8 and Interball satellites display the flapping movements of magnetopause in sequence with geomagnetic disturbances
Flapping motions of magnetosphere and vortexes formation Flapping movements might stimulate the substorm mesoscale processes
UV Aurora as observed by Polar satellite at July 15, 2000 auroral oval as predicted by GI , Alaska
Global scale auroras are known to be similar, but how about mesoscales (L=100-1000 km)? • ASC images: evolution of individual auroral structures can also have interhemispheric similarities. • The real conjugate point of a station can move hundreds (tens) of km in longitude (latitude) during one hour. • Reference: Sato et al., GRL 2005 Example: Interhemispheric relationships in meso-scale auroras
Geophysical network on Yamal peninsula at 1972-1991. Since 1972 there are analog recordings 20 mm/hour Since 1985 first digital magnetometers were installed onDixon, Bely Isl., Sabetta, Cape Kamenny, Salekhard, Analog data in WDC, digital data in Internet www.iki.rssi.ru/magbase
Public Outreach and Education Program in Seykha School: Polar Geomagnetic Disturbances as Indicator of Space Weather (will plan to use THEMIS data ) Seykha School, Yamal peninsula, Siberia, Russia geomagnetic latitude 65,0 degree
Thank you all colleagues that I have a chance to meet you !Sincerely , Alexander Zaitsev My personal wish a great success to THEMIS project under leadership of Dr.V.Angelopulos !