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

Plume of PI

Plasma sheet

lobesBL

Ionospheric (polar) wind

SOLAR WIND INDUCED ESCAPEE

B

MEX /ASPERA-3

SOLAR WIND INDUCED ESCAPE

COLD IONOSPHERIC IONS FAR IN TAIL

Cold ionospheric ions

Cold ionospheric ions

POLAR WIND

SOLAR WIND INDUCED ESCAPE

ESCAPE OVER REGIONS WITH STRONG CRUSTAL FIELDS

UV background

PLASMA SHEET

odswsw BVmn 2/22

22 / OOOon VmnB

P (ASPERA-3)P (MARSIS)dyn

M dayside

nightside

some part of momentum thermal pressure

2/1))1(

(2 r

kff swO

2/1))1(

(222 r

krff swO

O

O

n

nr 2

sw

O

nn

ESCAPE THROUGH PLASMA SHEET IS CONTROLLED BY SW VARIATIONS

K is momentum transfer factor (~0.1)

CMEs IMPACT VENUS AND MARS

MERCURY

VENUS4-5 June hours

hours

CME CME

CME CME

PP

PM~29 nPa

PM~5.3 nPa

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

Z, Rm

Y, Rm

SW MULTIPLE SHOCKLETS

PROTON NUMBER DENSITY

X, Rm

PROTON NUMBER DENSITYXZ-PLANE YZ-PLANE

MAGNETIC FIELD IN IONOSPHERE

IONOPAUSE OR… ?density

altitude

WHAT IS AN OBSTACLE FOR SW ?

ALFVEN SPEED

PILEUP BOUNDARYPHOTOELECTRON BOUNDARY

MARS

EARTH

INVERTED V STRUCTURES ON MARS AND AURORA?

DO WE UNDERSTAND CLEARLY WHAT IS INDUCED MAGNETOSPHERE?

SOLAR WIND WITH ALIGNED IMF

VENUS EXPRESS OBSERVATIONS

FIELD CONFIGURATION (POLOIDAL FIELDS)Without flow

With 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 ATFIRST SEEM STRAIGHTFORWARD, IT IS NOT A PARTICULARLYWELL-CONSTRAINED CONCEPT WHEN APPLIED TO VENUS AND MARS

WE NEED A MISSION WITH ADEQUATE PAYLOAD TO ADDRESS THESE QUESTIONS (MAVEN ?)

BACKUP

Launch, 18 November 20133-axis-stabilized, sun-pointing spacecraft75o inclination, 4.5-hour period orbitFive 5-day “deep dip” campaigns with periapsis altitudes down to the homopause (~125 km). Nominal periapsis: ~150 kmEight 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

OVER CRUSTAL FIELD REGIONS IONOSPHERIC EROSIONEROSION IS TRIGGERED BY SOME

UNKNOWN FACTORS

5th Alfven Conference, October 5, 2010, Sapporo, Japan

ELECTRON ACCESS VERSUS TOTAL CRUSTAL FIELD

E= - VxB

SW

By < 0

ALT

, km

By (IMF) > 0 By(IMF) < 0

B (400km),nT B (400km),nT

Ele

ctro

n Fl

ux

- By_IMF < 0 supports electron access to lower altitudes

Dubinin et al., AG, 20085th Alfven Conference, October 5,

2010, Sapporo, Japan

VnmBj ini

By (IMF) is negative

MAGNETIC FIELD AT LOW ALTITUDES

VnmBj ini

By (IMF) is positive

MAGNETIC FIELD AT LOW ALTITUDES

FLUX ROPE (Zhang et al. 2012) OR ELECTROJET

-Thermal escape of hydrogen is the dominant process Mean flux ~ 1.6 x 10 cm s8 -2 -1 ~ 2x 1026

s-1

 ~ 1026

s-1?