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С.П. Савин, Л.М. Зеленый, Е.А. Кузнецов (ИКИ РАН ) О взаимосвязи

С.П. Савин, Л.М. Зеленый, Е.А. Кузнецов (ИКИ РАН ) О взаимосвязи 2 фундаментальных явлений: концентрированных плазменных струй и альвеновского коллапса. February 13, 2001, CLUSTER. From: EGU06-A-00787 Kartalev, M. ; Savin, S. ; Dobreva, P.; Amata, E.; Shevyrev, N.

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С.П. Савин, Л.М. Зеленый, Е.А. Кузнецов (ИКИ РАН ) О взаимосвязи

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  1. С.П. Савин, Л.М. Зеленый, Е.А. Кузнецов (ИКИРАН) О взаимосвязи 2 фундаментальных явлений: концентрированных плазменных струй и альвеновского коллапса

  2. February 13, 2001, CLUSTER From: EGU06-A-00787Kartalev, M.; Savin, S. ; Dobreva, P.; Amata, E.; Shevyrev, N. From: EGU06-A-00787Kartalev, M.; Savin, S. ; Dobreva, P.; Amata, E.; Shevyrev, N. From: EGU06-A-00787Kartalev, M.; Savin, S. ; Dobreva, P.; Amata, E.; Shevyrev, N.

  3. Jets in SW? BS MP

  4. - (a) Cluster 3, Wk – ram pressure, Wt –ion thermal pressure, Wb– magnetic pressure, lagged Wk in SW (ACE); - (b) Cluster 3, angles sin-1(Vz/|V|),sin-1(Vy/|V|), GDCF – model prediction; Insert: jet directions in XZ plane; V=(-26;15;7) km/s – GSE velocity of the outermost jet as a whole; V=(-117;-37;31) km/s – velocity of the innermost jet. Dashed lines – the most deflected jets at 15.03 UT and at 14.97 UT.; - (c) comparison of Wk , [keV/cm3], ion density N, [1/cm3], and ion velocity (|V|/20, [(km/s)/20]),Cluster 3; - (d) the GSE electric component Ey from 4 Clusters

  5. Cluster 3, February 13, 2001 Jet inside MP? Deflected jets with compara-ble input from “Ni” and “V2” as a probable result of the MSH flow decay (-196;-230;90) km/s (-185;106;-219)km/s decay? Jet going to SW? 630 From magnetic disturbance at leading jet front Jet width ~ 200 km ~ (2-3) ri GDCF angle V_XY

  6. [ISSI book: CLUSTER AT THE MAGNETOSPHERIC CUSPS] IMFBz>0 A summary plot of the Cluster data during the cusp interval 05:00 - 10:00 UT on March 17, 2001. The panels show, from top to bottom, the HIA ion omni-directional energy fluxes, the HIA ion density, velocity and temperature, the FGM magnetic field, all from spacecraft 1, and the lagged IMF from the ACE spacecraft. (Figure provided by B. Lavraud) GSE, 6-12 UT

  7. Comparison of |B| on 4 SC (colors for SC 1-4: black, blue, violet, red) on March 17, 2001 associated with the MP jets (see Fig. 1); • Ram pressure Wk from 3 SC and that of SC1 at 11.995-12.075 UT (‘source jet’, dashed line, lagged); • Cluster 1: Wk (black), Wt – thermal ion pressure (blue), Wb – magnetic pressure (violet) and Wk in SW from Wind (magenta); • Ey from 4 Clusters.

  8. Plasma jet interaction with MP niMiVi2/2 < k (Bmax)2 /m0 [k ~ (0.5-1) – geometric factor] niMiVi2/2 > k (Bmax)2/m0 The plasma jets, accelerated sunward, often are regarded asproof for a macroreconnection; while every jet, accelerated in MSH should be reflected bya magnetic barrier forniMiVi2< (Bmax)2/m0in the absence of effective dissipation(that is well known in laboratory plasma physics)

  9. Ms~2 magnetosphere Ms~1.2 Wk_SW MSH

  10. While the low-latitude reconnection for the IMF Bz<0 can account for the jet ram pressure, itcan’t do so for the jet directionas all background energy densities on the jets’ paths are negligible versus the jet ram pressure and magnetic field gradient force is opposite to that required for the jet rotation IMF Bz<0

  11. Interball-1, June 19, 1998.(a)Tailward ion flux nVx from Interball-1, that of Geotail in SW and gasdynamic proxy (‘GDCF’); Insert: jet directions in XZ GSE plane relative to average MP and BS;

  12. [Shevyrev and Zastenker, 2002]

  13. In the jets kinetic energyWkin rises from ~ 5.5 to 16.5 keV/cm3For a reconnection acceleration till Alfvenic speed VA it is foreseen WkA ~ ni VA2/2 ~ const |B|2that requires magnetic field of 66 nT(120 nT inside MP if averaged with MSH) [Merka, Safrankova, Nemecek, Fedorov, Borodkova, Savin, Adv. Space Res., 25, No. 7/8, pp. 1425-1434, (2000)]

  14. Cluster3, February 2, 2003 Cluster1, February 2, 2003 (closer to the Earth) [eV/cc] Supersonic flow Wb Wk Magnetic barrier with ~sonic flow Wt cusp ‘plasma ball’ MP MP UT stagnant turbulent boundary layer Wb,t,k- cross-correlation < 0.35

  15. The Alfvenic collapse would stop at the scales of ~ ion gyroradius (i.e. at the MHD validity breaking), when magnetic field diffusion due to the finite ion gyroradius effects can neutralize the field growth • For collapse at ion gyroradius scale we estimate equilibrium from We estimate DH from characteristic shift by squared ion gyroradius ri2 at ion gyroperiod for the gradient scale ~ ion gyroradius

  16. Interball-1 MSH/stagnation region border encounter on April 21, 1996. • Comparison with switch-off slow shock [Karimabadi et al., 1995] displays strong magnetic barrier with pressure of the order of the MSH ram pressure. Inside ‘diamagnetic bubble’ ion temperature balances the external pressure

  17. Locations in Geocentric Solar Magnetospheric (GSM) coordinates of 208 magnetic barriers detected in Interball-1 magnetic field data between 1995 and 2000.

  18. eV/cc eV/cc (-263;-127;161)km/s (65;-215;-82)km/s GSE Reflected sunward jets (IMF Bz<0)Spiraling down the cusp throat (370 to B)

  19. reflected from cusp, spiralling upward reflected from MP jet, spiralling downcusp

  20. Alfven wave filamentation:Self-focusing instability[T. Passot et P.L. Sulem,Landau fluids for space plasmas]

  21. Time traces (in microseconds) in turbulent boundary layer in tokamak T-10, r=34 cm, • electric field Ep, [Volts] • (b) plasma density fluctuations n(t) [1/cm3] • particle flux due to ExB drift across magnetic field [1/(cm2 sec)]

  22. В ы в о д ы • «Плазменные струи», редко объясняемые пересоединением магнитных силовых линий, регулярно наблюдаются в магнитослое между ударной волной и магнитопаузой, их длительность ~ десятков секунд, рост их динамического давления на фоне невозмущенного солнечного ветра • - до 2-3 раз. • Примерно 20% струйпронизывают высокоширотную магнитопаузу, вызывая вторичное пересоединение и пролетая в межпланетное пространство через плазменную мантию или низкоширотный погранслой. • Некоторые их них отражаются геомагнитным полем независимо от межпланетного магнитного поля. • Одной из функций струйв магнитослое является «сброс» вниз по потоку до 40% импульса как в стационарном случае, так и при динамическом росте или падении внешнего динамического давления. При этом локальный баланс энергии поддерживается квази-покоящимися электромагнитными структурами в магнитослое. • Одним из источников ускорения струй является Альвеновский коллапс, в котором взрывообразный рост магнитного поля опрокидывающихся силовых линий вытесняет плазму вдоль силовых линий

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