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Auroral Electrojets and Boundaries of Plasma Domains in the Magnetosphere During Magnetically Disturbed Intervals : Volume 24, Issue 8 (13/09/2006)

By Feldstein, Y. I.

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Book Id: WPLBN0004001315
Format Type: PDF Article :
File Size: Pages 34
Reproduction Date: 2015

Title: Auroral Electrojets and Boundaries of Plasma Domains in the Magnetosphere During Magnetically Disturbed Intervals : Volume 24, Issue 8 (13/09/2006)  
Author: Feldstein, Y. I.
Volume: Vol. 24, Issue 8
Language: English
Subject: Science, Annales, Geophysicae
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Publication Date:
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications


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Kozyra, J. U., Cumnock, J. A., Popov, V. A., Prigancova, A., Tsurutani, B. T., Levitin, A. E.,...Gromova, L. I. (2006). Auroral Electrojets and Boundaries of Plasma Domains in the Magnetosphere During Magnetically Disturbed Intervals : Volume 24, Issue 8 (13/09/2006). Retrieved from

Description: Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Troitsk, Moscow Region, Russia. We investigate variations in the location and intensity of the auroral electrojets during magnetic storms and substorms using a numerical method for estimating the equivalent ionospheric currents based on data from meridian chains of magnetic observatories. Special attention was paid to the complex structure of the electrojets and their interrelationship with diffuse and discrete particle precipitation and field-aligned currents in the dusk sector. During magnetospheric substorms the eastward electrojet (EE) location in the evening sector changes with local time from cusp latitudes (Φ~77°) during early afternoon to latitudes of diffuse auroral precipitation (Φ~65°) equatorward of the auroral oval before midnight. During the main phase of an intense magnetic storm the eastward currents in the noon-early evening sector adjoin to the cusp at Φ~65° and in the pre-midnight sector are located at subauroral latitude Φ~57°. The westward electrojet (WE) is located along the auroral oval from evening through night to the morning sector and adjoins to the polar electrojet (PE) located at cusp latitudes in the dayside sector. The integrated values of the eastward (westward) equivalent ionospheric current during the intense substorm are ~0.5 MA (~1.5 MA), whereas they are 0.7 MA (3.0 MA) during the storm main phase maximum. The latitudes of auroral particle precipitation in the dusk sector are identical with those of both electrojets. The EE in the evening sector is accompanied by particle precipitation mainly from the Alfvén layer but also from the near-Earth part of the central plasma sheet. In the lower-latitude part of the EE the field-aligned currents (FACs) flow into the ionosphere (Region 2 FAC), and at its higher-latitude part the FACs flow out of the ionosphere (Region 1 FAC). During intense disturbances, in addition to the Region 2 FAC and the Region 1 FAC, a Region 3 FAC with the downward current was identified. This FAC is accompanied by diffuse electron precipitation from the plasma sheet boundary layer. Actually, the triple system of FAC is observed in the evening sector and, as a consequence, the WE and the EE overlap. The WE in the evening sector comprises only the high-latitude periphery of the plasma precipitation region and corresponds to the Hall current between the Region 1 FAC and Region 3 FAC. During the September 1998 magnetic storm, two velocity bursts (~2–4 km/s) in the magnetospheric convection were observed at the latitudes of particle precipitation from the central plasma sheet and at subauroral latitudes near the ionospheric trough. These kind of bursts are known as subauroral polarization streams (SAPS). In the evening sector the Alfvén layer equatorial boundary for precipitating ions is located more equatorward than that for electrons. This may favour northward electric field generation between these boundaries and may cause high speed westward ions drift visualized as SAPS. Meanwhile, high speed ion drifts cover a wider range of latitudes than the distance between the equatorward boundaries of ions and electrons precipitation. To summarize the results obtained a new scheme of 3-D currents in the magnetosphere-ionosphere system and a clarified view of interrelated 3-D currents and magnetospheric plasma domains are proposed.

Auroral electrojets and boundaries of plasma domains in the magnetosphere during magnetically disturbed intervals

Ahn, B.-H., Chen, G. X., Sun, W., Gjerloev, J. W., Kamide, Y., Sigwarth, J. B., and Frank, L. A.: Equatorward expansion of the westward electrojet during magnetically disturbed periods, J. Geophys. Res., 110, A01305, doi:10.1029/2004JA010553, 2005.; Akasofu, S.: Polar and magnetospheric substorm, D. Reidel Dordrecht-Holland, 1968.; Akasofu, S.-I.: Exploring the secrets of the aurora, Dordrecht, Kluwer Academic Publ., 2002.; Akasofu, S.-I, Chapman, S., and Meng, C.-I.: The polar electrojet, J. Atmos. Terr. Phys., 27, 1275–1305, 1965.; Baker, K. B. and Wing, S.: A new magnetic coordinate system for conjugate studies at high latitudes, J. Geophys. Res., 94, 9139–9143, 1989.; Boström, R.: A model of the auroral electrojets, J. Geophys. Res., 69, 4983–4994, 1964.; Baumjohann, W., Untiedt, J., and Greenwald, R. A.: Joint two-dimensional observations of ground magnetic and ionospheric electric fields associated with auroral zone currents. 1. Three-dimensional current flows associated with a substorm-intensified eastward electrojet, J. Geophys. Res., 83, 1963–1978, 1980.; Brandt, P. C., Mitchel, D. G., Ebihara, Y., Sandel, B. R., Roelof, E. C., Burch, J. L., and Demajistre, R.: Global IMAGE/HENA observations of the ring current: examples of rapid response to IMF and ring current-plasmasphere interaction, J. Geophys. Res., 107, SMP12, 1359, doi:10.1029/2001JA000084, 2002a.; Brandt, P. C., Ohtani, S., Mitchel, D. G., Fok, M.-C., Roelof, E. C., and Demajistre, R.: Global ENA observations of the storm main phase ring current: implication for skewed electric fields in the inner magnetosphere, Geophys. Res. Lett., 29, doi:10.1029/2002GL015160, 2002b.; Burch, J. L., Mitchel, D. G., Sandel, B. R., Brandt, B. C., and Wuest, M.: Global dynamics of the plasmasphere and ring current during magnetic storms, Geophys. Res. Lett., 38, 1159–1162, 2001.; Burch, J. L., Lewis, W. S., Immel, T. J., Anderson, P. C., Frey, H. U., Fuselier, S. A., Gerard, J.-C., Mende, S. B., Mitchell, D. G., and Thomsen, M. F.: Interplanetary magnetic field control of afternoon sector detached proton auroral arcs, J. Geophys. Res., 107, 1251, doi:10.1029/2001JA007554, 2002.; Chapman, S.: The electric current system of magnetic storm, Terr. Magn. Atmos. Elec., 40, 349–370, 1935.; Clauer, C. R., Alexeev, I. I., Belenkaya, E. S., and Baker, J. B.: Special features of the September 24–27, 1998 storm during high solar dynamic pressure and northward interplanetary magnetic field, J. Geophys. Res., 106, 25 695–25 711, 2001.; Evlashin, L. S. and Maltsev, Yu. P.: Dependence intensity of different types auroral emission from geomagnetic activity, (in Russian), Geomagn. Aeron., 44(3), 311–315, 2004.; Feldstein, Y. I.: The morphology of aurora and geomagnetism, Aurora and Airglow, The Academy of Sciences of the U.S.S.R., (in Russian), 10, 121–126, 1963.; Feldstein, Y. I.: Magnetic field variation in nearpole region during magnetically quiet periods and interplanetary magnetic fields, Space Sci. Rev., 18, 777–861, 1976.; Mansurov, S. M.: New evidence of the relationship between magnetic field in space and on the Earth, (in Russian), Geomagn. Aeronom, 9, 768–773, 1969.; Feldstein, Y. I. and Galperin, Yu. I.: Structure of the auroral precipitations in the nightside sector of the magnetosphere, Cosmic Research, 34(3), 209–227, 1996.; Feldstein, Y. I. and Zaitzev, A. N.: The current system of SD-variations in high latitudes for the winter season during the IGY, Geomagn. Aeron., 5, 1123–1128, 1965.; Feldstein, Y. I., Sumaruk, P. V., and Shevnina, N. F.: To the diagnostics of the azimuthal component of the interplanetary magnetic field, C. R. Acad. Sci. USSR, 222, 833–836, 1975.; Feldstein, Y. I., Gromova, L. I., Popov, V. A., and Grafe, A.: Auroral electrojet dynamics during magnetic storms, Proc. ICS-3, Versailles, May, 1966, ESA SP-389, 75&a


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