The Relief of Plasma Pressure and Generation of Field-Aligned Currents in the Magnetosphere

Pavel Sedykh

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DOI: 10.4236/ijaa.2011.12004                

Abstract

A combined action of plasma convection and pitch-angle diffusion of electrons and protons leads to the formation of plasma pressure distribution in the magnetosphere on the night side, and, as it is known, steady electric bulk currents are connected to distribution of gas pressure. The divergence of these bulk currents brings about a spatial distribution of field-aligned currents, i.e. magnetospheric sources of ionospheric current. The projection (mapping) of the plasma pressure relief onto the ionosphere corresponds to the form and position of the auroral oval. This projection, like the real oval, executes a motion with a change of the convection electric field, and expands with an enhancement of the field. Knowing the distribution (3D) of the plasma pressure we can determine the places of MHD-compressor and MHD-generators location in the magnetosphere. Unfortunately, direct observations of plasma distribution in the magnetosphere are faced with large difficulties, because pressure must be known everywhere in the plasma sheet at high resolution, which in situ satellites have been unable to provide. Modeling of distribution of plasma pressure (on ~ 3-12 Re) is very important, because the data from multisatellite magnetospheric missions for these purposes would be a very expensive project.

Keywords

Magnetosphere, Plasma Convection, Plasma Pressure, Field-Aligned Currents

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	E. E. Antonova, N. Yu Ganushkina, “Azimuthal Hot Plasma Pressure Gradients and Dawn-Dusk Electric Field Formation,” Journal of Atmospheric and Solar- Terrestrial Physics, Vol. 59, No. 11, 1997, pp. 1343-1354. doi:10.1016/S1364-6826(96)00169-1
[2]	E. E. Antonova, “Radial Gradients of Plasma Pressure in the Magnetosphere of the Earth and the Value of Dst Variation,” Geomagnetism and Aeronomy, Vol. 41, No. 2, 2001, pp. 148-156.
[3]	P. De Michelis, I. A. Daglis and G. Consolini, “An Average Image of Proton Plasma Pressure and of Current Systems in the Equatorial Plane Derived from AMPTE/ CCE-CHEM Measurements,” Journal of Geophysical Re- search, Vol. 104, No. 12, 1999, pp. 28615- 28624.
[4]	A. S. Kovtukh, “Radial Profile of the Pressure of the Storm Ring Current as a Function of Dst,” Cosmical Research, Vol. 48, No. 3, 2010, pp. 218-238, (in Russian).
[5]	M. V. Stepanova, E. E. Antonova, J. M. Bosqued and R. Kovrazhkin, “Azimuthal Plasma Pressure Reconstructed By Using the 3 Aureol-3 Satellite Data During Quiet Geomagnetic Conditions,” Advances in Space Research, Vol. 33, No. 5, 2004, pp. 737-741.
[6]	C. F. Kennel, “Consequence of a Magnetospheric Pla- sma,” Review of Geophysics, Vol. 7, No. 1-2, 1969, pp. 379-419. doi:10.1029/RG007i001p00379
[7]	E. A. Ponomarev, “Mechanism of Magnetospheric Substorms,” Nauka, Moscow, 1985, p. 157, (in Russian).
[8]	E. A. Ponomarev and P. A. Sedykh, “How Can We Solve the Problem of Substorms? Geomagnetism and Aeronomy,” Pleiades Publishing, Vol. 46, No. 4, 2006, pp. 560-575.
[9]	K. Birkeland, “The Norvegian Auгora Polaris Expedition 1903-1908,” Christiania, Vol. 1, 1913, pp. 1220-1224.
[10]	R. A. Bostrom, “A Model of the Auroral Electrojets,” Journal of Geophysics Research, Vol. 69, No. 23, 1964, pp. 4983-4987. doi:10.1029/JZ069i023p04983
[11]	P. A. Sedykh and E. A. Ponomarev, “The Magnetosphere-Ionosphere Coupling in the Region of Auroral Electrojets,” Geomagnetism and Aeronomy, Pleiades Publishing Inc., Vol. 42, No. 5, 2002, pp. 613-618.
[12]	V. M. Vasyliunas, “Mathematical Models of Magnetospheric Convection and its Coupling to the Ionosphere,” In: B. M. McCormac Ed., Particles and Fields in the Magnetosphere, Higham, 1970, pp. 60-71.
[13]	B. A. Tverskoy, “Electric Fields in the Magnetosphere and the Origin of Trapped Radiation,” Solar-Terrestrial Physics, Dordrecht, 1972, pp. 297-317.
[14]	T. Iijima and T. A. Potemra, “Large-Scale Characteristics of Field-Aligned Currents Associated with Substorms,” Journal of Geophysics Research, Vol. 83, No. A2, 1978, pp. 599-615. doi:10.1029/JA083iA02p00599
[15]	E. A. Ponomarev, P. A. Sedykh and V. D. Urbanovich, “Bow Shock as a Power Source for Magnetospheric Pro- cesses,” Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 68, No. 6, 2006, pp. 685-690. doi:10.1016/j.jastp.2005.11.007
[16]	S. I. Solovyev, “Magnetosphere-Ionosphere Response to Magnetosphere Compression by the Solar Wind,” Proceeding of XXVI Annual Seminar, Apatity, 2003, pp. 41-44.
[17]	C. L. Waters, B. J. Anderson and K. Liou, “Estimation of global Field-Aligned Currents Using the Iridium System Magnetometer Data,” Geophysical Research Letters, Vol. 28, No. 11, 2001, pp. 2165-2168. doi:10.1029/2000GL012725
[18]	M. Harell, R. A. Wolf and P. H. Reif, “Quantitative Simulation of a Magnetospheric Substorm, 1. Model Logic and Overview,” Journal of Geophysical Research, Vol. 86, No. A4, 1981, p. 2217. doi:10.1029/JA086iA04p02217
[19]	R. A. Wolf, Y. Wan, X. Xing and J. C. Zhang, “Sazykin S. Entropy and Plasma Sheet Transport,” Journal of Geophysical Research, Vol. 114, 2009. doi:10.1029/2009JA014044
[20]	L. R. Lyons, C. Wang, M. Gkioulidou and S. Zou, “Connections between Plasma Sheet Transport, Region 2 Currents, and Entropy Changes Associated with Convection, Steady Magnetospheric Convection Periods, and Substorms,” Journal of Geophysical Research, Vol. 114, 2009, p. 14. doi:10.1029/2008JA013743