Solar Wind Induced Escape on Mars and Venus

Solar Wind Induced Escape on Mars and Venus Mutual Lessons from Different Space Missions E. Dubinin Max-Planck Institute for Solar System Research, Katlenburg-Lindau, Germany

SOLAR WIND INDUCED ESCAPE E B Plume of PI lobes BL Plasma sheet Ionospheric (polar) wind MEX /ASPERA-3

SOLAR WIND INDUCED ESCAPE

COLD IONOSPHERIC IONS FAR IN TAIL POLAR WIND Cold ionospheric ions

SOLAR WIND INDUCED ESCAPE

ESCAPE OVER REGIONS WITH STRONG CRUSTAL FIELDS UV background

PLASMA SHEET P (ASPERA-3) dyn P (MARSIS) M dayside nightside some part of momentum thermal pressure

ESCAPE THROUGH PLASMA SHEET IS CONTROLLED BY SW VARIATIONS K is momentum transfer factor (~0. 1)

CMEs IMPACT VENUS AND MARS

MERCURY CME PP PM~29 n. Pa 4 -5 June hours VENUS CME hours CME PM~5. 3 n. Pa

MARS (MARSIS DATA) Sequential plot for local |B|: 9475, 9481, 9482, 9487

MARS (MARSIS DATA) Sequential plot for ionospheric peak ne: 9475, 9481, 9482, 9487

VENUS MARS Different modes of ELS

- OTHER OPEN QUESTIONS?

- ION FORESHOCK ? (There are no reflected protons upstream of the nose of the Martian BS. Ion foreshock lies entirely downstrem of the subsolar point) - HOT OXYGEN CORONA? (There are no ASPERA observations of oxygen ions which could be reliably identified as originated from hot oxygen corona)

’FILAMENTATION’ OF PLASMA FLOW AROUND MARS 2050 2100 2110 2120 2130

PLASMA FILAMENTATION IN MULTI-FLUID AND HYBRID SIMULATIONS YZ-PLANE XZ-PLANE PROTON NUMBER DENSITY MULTIPLE SW Z, Rm X, Rm Y, Rm

MAGNETIC FIELD IN IONOSPHERE

IONOPAUSE OR… ? density altitude

WHAT IS AN OBSTACLE FOR SW ? PHOTOELECTRON BOUNDARY PILEUP BOUNDARY ALFVEN SPEED

INVERTED V STRUCTURES ON MARS AND AURORA? M A R S E A R T H

DO WE UNDERSTAND CLEARLY WHAT IS INDUCED MAGNETOSPHERE? SOLAR WIND WITH ALIGNED IMF

VENUS EXPRESS OBSERVATIONS

FIELD CONFIGURATION (POLOIDAL FIELDS) Without flow With flow and leakage of dipole field outwards

REVERSED DRAPING OR WRAPPING EFFECT

REVERSED DRAPING OR WRAPPING EFFECT

CURRENT PATTERN

E+ - hemisphere E- - hemisphere

CONCLUSIONS WHILE THE IDEA OF AN INDUCED MAGNETOSPHERE AT FIRST SEEM STRAIGHTFORWARD, IT IS NOT A PARTICULARL WELL-CONSTRAINED CONCEPT WHEN APPLIED TO VENUS AND MARS WE NEED A MISSION WITH ADEQUATE PAYLOAD TO ADDRESS THESE QUESTIONS (MAVEN ? )

BACKUP Launch, 18 November 2013 3 -axis-stabilized, sun-pointing spacecraft 75 o inclination, 4. 5 -hour period orbit Five 5 -day “deep dip” campaigns with periapsis altitudes down to the homopause (~125 km). Nominal periapsis: ~150 km Eight science instruments, grouped into three packages

The MAVEN Science Instruments Mass Spectrometry Instrument Remote-Sensing Package Particles and Fields Package

BACKUP

ESCAPE FLUXES AS A FUNCTION OF SW FLUX

IONOSPHERIC EROSION IS TRIGGERED BY SOME OVER CRUSTAL FIELD REGIONS UNKNOWN FACTORS 5 th Alfven Conference, October 5, 2010, Sapporo, Japan

ELECTRON ACCESS VERSUS TOTAL CRUSTAL FIELD By (IMF) > 0 By(IMF) < 0 ALT, km SW Electron Flux By < 0 E= - Vx. B B (400 km), n. T - By_IMF < 0 supports electron access to lower altitudes 5 th Alfven Conference, October 5, 2010, Sapporo, Japan Dubinin et al. , AG, 2008

MAGNETIC FIELD AT LOW ALTITUDES By (IMF) is negative

MAGNETIC FIELD AT LOW ALTITUDES By (IMF) is positive FLUX ROPE (Zhang et al. 2012) OR ELECTROJET

-Thermal escape of hydrogen is the dominant process 26 8 -2 Mean flux ~ 1. 6 x 10 cm s -1 -1 ~ 2 x 10 s ? 26 -1 ~ 10 s