Институт космических исследований Российской Академии наук

1. Необычная магнитосфера Марса – сопоставление результатов предшествующих и последних исследований М. Веригин Институт космических исследований Российской Академии наук Пятая конференция ОФН 15 «Физика плазмы всолнечной системе» 812 февраля 2010 г., ИКИ РАН

2. Содержание • Mariner 4 , Марс 2, 3, 5 – ранние измерения • Марс 3 – первые наблюдения намагниченности марсианской коры 21 января, 1972 • о магнитном моменте Марса • особенности околомарсианских плазменных границ: • стабильность ударной волны у терминатора; • отсутствиеrV2инвариантности магнитопаузы; • очень большой отход ударной волны от Марса при малых Maв солнечном ветре; • олияние неоднородной намагниченности марсианской коры на положение магнитопаузы; • конкуренция двух механизмов ускорения ионов в магнитном хвосте Марса • об источниках ночной ионосферы планеты

3. Mariner 4, Mars 2,3,5 observations Марс 2-3, 5, 1971-72, 1974 Mariner 4, July 15, 1965 • Martian magnetosphere discovery • multiple bow shock crossings • Martian bow shock discovery Mars 2 1 - 17.12.71 2 - 08.01.72 3 - 12.05.72 Мars 3 4 - 15.12.71 5 - 09.01.72 6 - 21.01.72 7 - 21.01.72 Мars 5 8 - 13.02.74 9 - 20.02.74 10 - 22.02.74 11 - 24.02.74

4. Mars 3 magnetospheric observations Dolginov et al., Doklady AN SSSR, 207, No.6, 1296-1299, 1972 Dolginov et al., JGR, 81, No.19, 3353-3362, 1976 • Strong (~27 nT) and regular magnetic field in the vicinity of Mars 3 closest (~ 1500 km) approach to the day side of the planet • Originally interpreted as an evidence of planetary dipole magnetic field Mm = 2.4x1022 G cm3 • LaterRussell et al. (GRL, 5, No.1, 81-84, 1978) inferred that • “…observed magnetic field was draped over the Martian obstacle as expected if the field were simply shocked and compressed solar wind magnetic field.”

5. Inconsistency with simple IMF draping Mars 3, Jan. 21, 1972 but: • Magnetic field direction has discon-tinuity around the Mars 3 closest approach region (orange arrows) • Magnetic field direction is inconsis-tent to those one expected for simple draping in the closest approach region Hence : • “…Mars most probably possesses a small intrinsic field magnetosphere.” • Slavin & Holzer, JGR, 87, No.B12, 10285-10296, 1982

6. What was below Mars 3 on Jan.21, 1972 ? Mars 3 orbit Jan. 21, 1972 projection to surface Horizontal magnetic field Connerneyet al., GRL., 28, No.21, 4015–4018, 2001 • Mars 3 observed strong and regular magnetic field exactly above the region of the strongest magnetization of the Martian crust Total magnetic field

7. Do MGS crustal field direction corresponds to those one observed by Mars 3 ? YES ! • Comparison of Mars 3 magnetic field with those one of MGS provides evidence that Mars 3 really detected the magnetic field of Martian crust in the early 1972. Verigin & Slavin,EPSC2006-A-00385. • This observations was not properly interpreted before MGS crustal magnetization discovery.

8. On planetary magnetic moment of Mars Prior to Phobos 2: Luhmann et al., 1992 Mars Global Surveyor: Mm 2 · 1020гс · см3 (Acuna et al., 2001)??? with Bequat 0.5 nT Phobos 2: Mm 8 · 1021гс · см3 magnetopause model by Verigin et al. (1997) butBequat ~ 10 nT(Arkani-Hamed, 2001)  Mm~ 4· 1021гс · см3

9. Mars Global Surveyor: Connerney et al., 2001 On planetary magnetic moment of Mars Nothern hemisphere: “TO THE PLANET” Southern hemisphere: “FROM THE PLANET”  • There is an essential dipole component exists in the multipole moment of planet Mars • Further methodology development is necessary for its accurate determination, including consideration of current systems produced by solar wind – Mars interaction

10. Phobos 2 – detailed BS and MP position dependencies on rV2 Martian magnetotail diameter D ~ 550 (V2)-1/5.9км similar to geomagnetic tail compressibility Distance to terminator bow shock R ~ 6000 (V2)-0.02км practically independent onthe V2 !!! Phobos 2 statistics of the bow shock and magnetopause crossings

11. Martian magnetopause shape and variations MGS rV2 dependent Martian magnetopause model Phobos 2 rV2 dependent Martian magnetopause model Verigin et al., Adv. Space Res., 33, 12, 2222, 2004 • Martian magnetopause is not of rV2 invariant • Stagnation of the magnetopause nose position and increase of its curvature radius with increasing of rV2 are explaining rV2 independence of the bow shock terminator position, found by Phobos 2 data

12. Distant BS excursions at small solar wind Ma values Modeled typical (BS3, MP3)and distant (BS1, MP1) positions of the Martian bow shock and magnetopause Upstream solar wind on March 24, 1989 • Unusually distant Martian bow shock excursions were initiated by extremely small upstream V2 and Ma values Verigin et al., Sp.Sci.Rev.,111, 233, 2004.

13. Influence of the Martian crustal magnetization on the magnetopause position Equatorial magnetotail diameter dependence on the longitude of the upstream terminator (Phobos 2) Increase of the magnetopause height over magnetized regions (MGS data) Verigin et al., Adv. Space Res., 28 (6), 885, 2001; 33(12), 2222, 2004. • Localized Martian crust magnetization increases downstream magnetopause height by 500-1000 km additionally.

14. Martian magnetotail magnetic field and plasma arrangement by IMF Mars Express ASPERA 3 experiment Barabash et al., Science 315, 502, 2007 plasma sheet Yeroshenko et al., GRL, 17, No.9, 885, 1990 Schwingenschuh et al., Adv. Space Res., 12(9), 213, 1992

15. Loss of planetary ions through plasmasheet Phobos 2, Feb. – Mar. 1989, High SA Ф~ 5.1024 ions/s Direct Simulation Monte Carlo (DSMC) + 3D Mars Thermosphere General Circulation (MTGCM) modeling Valeille, Combi, Tenishev, Bougher, Nagy, Icarus, doi: 10.1016/j.icarus.2008.08.018, 2008 Verigin et al., Planet. Space Sci. 39, 131, 1991 MEX, May 2004 – May 2006, Low SA Ф~ 1.6.1023 0+/s +1.5.102302+/s + + 0.8.1023C02+/s ~ 4.1023ions/s Barabash et al., Science 315, 502, 2007 • Both experimental estimates are in qualitative agreement with variation of the planetary ion escape rates within solar cycle, although • the escape of Martian ions integrated over near-planetary region is only the minor part of planetary ion escape rate (ФhighSA~ 2.4.1026 0/s, Valeille, et al., 2008). • Direct measurement of total ion escape rate are highly welcomed.

16. Hot oxygen corona is the mainchannel of Martian ions loss – how to measure it? Solar wind pre bow shock deceleration Phobos 2, High SA Comparison with DSMC+MTGCM modeling Li ~ 4x106 km ! total pick-up ion flux F < 2·105 (104km / r ) cm-2s-1 pick-up ion number density cm-3 Kotova et al., JGR, 102, A2, 2165, 1997 • Measurements of pick-up ion radial profile, starting from ~ 106 km to Mars, can provide reliable evaluation of the total Martian ions loss rate

17. Competing processes of Martian plasmasheet ion acceleration 1) Magnetic field line stress acceleration  with and  2) Across magnetotail electric field E acceleration Ion energy increaseEiafter its cyclotron diameter 2Rc displacement across the magnetotail  

18. 2 m c / n y d , e r u s s e r p m a r n o i y v a e h 1 10 100 1000 2 1 / 2 3 3 1 / 2 B * B / T , n T / ( 1 0 K ) ^ II Competing processes of Martian plasmasheet ion acceleration V2 > 610-9 дин/см2V2< 610-9 дин/см2 Kotova et al., Phys. Chem. Earth (C), 25(1-2), 157, 2000 Across magnetotail electric field acceleration prevails –”magnetospheric obstacle” Magnetic field line stress acceleration prevails – “induced obstacle”  • Change of the plasmasheet ion acceleration process take place at that rV2 value when magnetopause nose position starts to increase after its stagnation at high ram pressures

19. Martian nightside ionosphere source • Phobos 2 electron spectra measurements (HARP experiment) revealed permanent presence electron fluxes of J0 ~ 108cm-2s-1in the areomagnetic tail with energies sufficient for ionization of Martian neutral atmosphere constituents

20. Martian nightside ionosphere source Estimated peak nemax of the night-side ionization layer corresponds to that one observed byradio occultations of Mars 4,5 and Viking 1,2 spacecraft. “Why was the peak of nightside ionization observed in 100% of th s/c radio occultations at but in only 40% of radio occultations at Mars? The reason may be connected with the partial screening of the Martian nightside atmosphere by a weak intrinsic magnetic field of the planet which is completely absent in the case of Venus” Verigin et al., JGR, 96(A11), 1991 Haider et al., JGR, 97, 10637, 1992

21. Martian nightside ionosphere source:comparison with subsequent observations Comparison with SPICAM UV spectroscopy measurements aboard Mars Express Magnetization of Martial crust that partially screens planetary atmosphere was really found… Acuna et al., JGR, 106(E10), 23400, 2001 Comparison of nightsidelow altitude electron spectra measured by MEX/ASPERA 3 and MGS/ER (thick line) with Phobos 2/HARP (color) ones used for nightside ionization calculations Leblanc et al., JGR, 111(A09313), doi:10.1029/2006JA011763, 2006 Detailed multi-ion nightside Martian ionosphere model is available now, considering e-impacts and galactic cosmic ray ionization until planetary surface Haider et al., JGR, 112(A12309), doi:10.1029/2007JA012530, 2007 Brain et al., GRL, 33, L01201, 2006 Dubinin et al., Pl.Sp.Sci., 56, 846, 2008

22. Спасибо за внимание ! Пятая конференция ОФН 15 «Физика плазмы всолнечной системе» 812 февраля 2010 г., ИКИ РАН