Spatial distribution of the field-aligned current density in the polar ionosphere and the contribution of magnetosound waves     

Mishin  V. M.  Saifudinova  T. I.  Karavaev  Yu. A.  Kurikalova  M. A.  Bazarzhapov  A. D. 《Geomagnetism and Aeronomy》2009,49(7):975-982

The regular appearance of the chain of oppositely directed field-aligned current (FAC) pairs near the noon-midnight meridian during three considered substorms has been described. The FAC pairs (FACs flowing into the ionosphere in the morning and flowing out of this region in the evening and vice versa) are observed in each of three Iijima and Potemra zones. The FAC direction in the fixed LT sector periodically varies along the chain. The scenario, according to which each FAC pair (seven pairs) is identified with a hump or trough of one of the waves propagating from the Earth and toward the Earth in different magnetospheric domains, has been described. The estimated wave velocities differ from ∼100 to >1000 km/s depending on the propagation region but everywhere agree with the corresponding velocities of magnetosound waves (MSWs). The hypothesis is proposed, according to which these MSWs are excited by plasma ejection during current disruption and reconnection near the dayside magnetopause and in the near/middle regions of the nightside tail.  相似文献   

Substorms on February 26, 2008: Synthesis of the outside-in and inside-out scenarios     

V. M. Mishin  Z. Pu  L. A. Sapronova  M. V. Tolochko  T. I. Saifudinova  S. I. Solovyev 《Geomagnetism and Aeronomy》2010,50(8):997-1002

Data of measurements made onboard THEMIS satellites and data of high-latitude system of ground magnetometers that were processed using the magnetogram inversion technique are used to describe the time sequence of the basic processes of substorms on February 26, 2008. The conclusion is made that this sequence of events does not agree with either of the two known substorm scenarios, Outside-In and Inside-Out, but agrees with the result of their synthesis.  相似文献   

Spontaneous substorms and ordered type of magnetospheric disturbances during the superstorm of November 20, 2003     

V. M. Mishin  M. Foerster  T. I. Saifudinova  A. D. Bazarzhapov  Yu. A. Karavaev  L. A. Sapronova  S. I. Solovyev 《Geomagnetism and Aeronomy》2007,47(4):429-441

The interval 0000-1400 UT of the superstorm of November 20, 2003, has been studies based on the ACE/WIND data and the MIT2 magnetogram inversion technique. The distributions of the electric potential and currents, field-aligned currents, and Joule heat in the ionosphere have been calculated. The variable magnetotail length and powers coming into the magnetosphere, ionosphere and ring current have been estimated. The selected superstorm intervals, when it became possible to identify the disturbance mode produced by the interaction between the variable solar wind dynamic pressure and IMF effects, have been described. Spontaneous substorms, two types of driven responses to changes in IMF or in the solar wind dynamic pressure (P _d ), zero events at simultaneous jumps of IMF and P _d , and a previously unknown mode of saturation of the ionospheric electric field at a redistribution of the energy coming into the magnetosphere between the ionosphere and ring current are among the selected modes.  相似文献   

The scenario of magnetospheric substorms on the example of events on February 26, 2008     

V. M. Mishin  Z. Pu  L. A. Sapronova  M. V. Tolochko  T. I. Saifudinova  S. I. Solovyev 《Doklady Earth Sciences》2010,433(2):1053-1056

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Energetics of the magnetospheric superstorm on November 20, 2003     

Karavaev  Yu. A.  Sapronova  L. A.  Bazarzhapov  A. D.  Saifudinova  T. I.  Kuz’minykh  Yu. V. 《Geomagnetism and Aeronomy》2009,49(7):961-969

The magnetospheric storm on November 20, 2003 was one of two greatest events in 1957–2003. The D _st^* index reached −472 nT, the polar cap potential drop exceeded 200 kV, the polar cap boundary expanded up to Φ = 60°, the plasma layer density in the synchronous orbit reached 5 cm⁻³, and the inner edge of the plasma sheet penetrated up to L ∼ 1.5R _E. The sequence of disturbance modes including some previously unknown is described. The distribution of the total power input into the magnetosphere between the ionosphere (power Q _i) and the ring current (Q _DR), as well as the relative roles of the spontaneous substorms and the driven disturbances in the creation of the DR current, is analyzed. The values of the parameter α = Q _DR/Q _i are calculated with a step of 5 min. It is shown that intervals with α ≪ 1 and with maximums α ≫ 1 were observed in the events under consideration. These results contradict the dominant opinion that the energy input into the magnetosphere during disturbances is primarily dissipated in the ionosphere. The two types of α maximums are observed: one in the mode of a prevailing spontaneous substorm and the other in the mixed mode of the substorm and driven disturbance. It is concluded that both types of the maximums and corresponding enhancements of the DR current appeared due to the plasma turbulization processes in the substorm current wedge. The parameter α appears to slowly increase from α ≪ 1 to α > 1 with increasing activity level; this trend supports the driven model of creating the DR current due to an increase in the electric field of the solar wind.  相似文献