Solar wind interaction with the comet Halley and Venus

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Solar wind interaction with the comet Halley and
Venus

• K. Murawski
• University of M. Curie Sklodowska

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Outline

• Overview of solar wind interaction with
• magnetic and non-magnetic bodies
• Numerical simulations of the solar wind
• interaction with Venus
• Numerical simulations of the solar wind
• interaction with the comet Halley
• Summary

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A global view of the Heliosphere
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Solar system - Icy Matter ...
Jan Oorts Cometary Cloud
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Outskirts of the Solar system - Comets
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Properties of the solar wind

• highly conducting plasma
• electrons, protons alpha-particles
• radial expansion

• magnetic field frozen in the plasma
• SW super-sonic super-alfvénic

• ne 5 cm-3
• T 105 K
• BIMF 5 nT
• vsw 400 km/s
• vA 30 - 50 km/s
• cS 60 km/s

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TYPES OF INTERACTION WITH THE SOLAR WIND
GANIMEDE
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Simplest caseEarth's MOONNO magnetic fieldNO
atmosphere
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MOON type

• no magnetic field
• negligibly thin atmosphere

• insulating material
• submerged in a flowing plasma
• absorption of particles
• no bow shock upstream
• plasma absorption wake
• magnetic field parallel to the upstream flow ? no
  effect
• magnetic field perpendicular to the flow ?
  minimal effect

Illustration of the interplanetary plasma flow
and magnetic-field perturbation by the
nonconducting moon. The wake created by
solar-wind absorption closes more quickly when
the magnetic field is not aligned with the
undisturbed flow.
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SW interactions with magnetized bodiesand an
atmosphere
Obstacle magnetosphere
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EARTH type (Jupiter, Saturn)

• strong magnetic field
• substantial atmosphere

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SW interactions with magnetized bodiesbut
without an atmosphere
Obstacle magnetosphere
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MERCURY - type

• strong magnetic field
• no gravitationally bound atmosphere

• Similarities and differences with Earth
• Magnetosphere
• Absence of an atmosphere and ionosphere
• Solar wind conditions
• Mercury has a larger fractional volume of its
  magnetosphere
• no stable trapping regions
• closed magnetic flux tubes
• Solar wind primary source of magnetospheric
  plasma
• Plasma sheet higher densities

0.382 AU Mercury
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COMETSNO internal magnetic fieldbut atmosphere
Obstacle exosphere
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What is Solar Wind?

• COMETS

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Comet Structure

• Nucleus main solid core of the comet.
• Tail gas and dust particles released by the
  comet.
• Coma gases and dust released by the comet when
  energy from the sun heats the comet and causes
  the solid materials to turn into a gas.

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Comet Tails

• Comets develop tails only when the get close
  enough to the Sun.
• Comet tails always point away from the SunThis
  is how scientists first realized the existence of
  solar wind.

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Comet type

• no internal magnetic field
• substantial atmosphere

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• Numerical model - MHD

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• Numerical results

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• Numerical results

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• Numerical results

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• Numerical results

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• Numerical results

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• Numerical results

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SW interactions with unmagnetized bodies with a
substantial atmosphere
Obstacle ionosphere
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Venus
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VENUS type

• weak magnetic field or non at all
• substantial atmosphere

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Structure of the Ionosphere
Brace and Kliore, 1991
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Location of the obstacle boundary
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Induced magnetotail
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Pick up and escape processes
Escape
Energetic neutral atoms (ENAs)
Escape
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Ionospheric magnetic field
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(No Transcript)
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Altitude (Km)
Number Density (cm-3)
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Numerical model - Draping magnetic field lines
Solar wind
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Physical model 2 component MHD
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Parameters of the physical model
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Pressure distribution
Interaction region
IMF
bow shock
magnetic barrier
ionosphere
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Pressure profiles in the subsolar region
X
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Plasma profiles
X
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Magnetic field lines and nightside ionosphere
Z
XZ plane
Solar wind
X
IMF
Y
XY plane
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Concluding remarks

• Flowing plasma interactions with various types of
  
• magnetized planets or
• unmagnetized / weakly magnetized bodies
• Each plasma interaction has distinctive features
• Earth magnetic field and atmosphere
• Mercury magnetic field but NO atmosphere
• Moon like bodies neither a magnetic field nor
  an atmosphere
• Venus and Mars no internal magnetic field but
  a substantial atmosphere
• Comets atmospheres with insignificant bodies

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Thank you!
kmur_at_kft.umcs.lublin.pl