Space Physics at Mars

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Space Physics at Mars

• Paul Withers
• 2006.03.13
• Journal Club Research Talk
• Center for Space Physics, Boston University

Aims Show students how principles of space
physics apply at Mars Emphasize wide range of
interesting phenomena Stimulate interest in
Mars-related research projects
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Same Physics, Different Place

• Interaction of solar wind and magnetic field
• Aurora
• Ionospheric physics
• Solar flares
• Meteors
• Plasma instabilities and currents
• Observations
• Magnetometers and charged particle detectors
• Thousands of Ne(h) profiles
• Topside ionospheric sounder

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Magnetic Field What happens when the strength of
the magnetic field varies over horizontal
distances of 100 km? What happens when there
are multiple cusps close to multiple equators?
Expect lots of inhomogeneities Longitude and
local time matter, not just local time
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Aurora have been seen (once) on Mars Electron
data suggest they occur often What are the
effects of martian atmospheric chemistry?
Aurora
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Ionospheric Profiles
Earth (Hargreaves, 1992) F layer due to EUV
photons E layer due to soft X-rays D layer due to
hard X-rays (Over-simplification...)
Mars (MGS RS data) Main peak at 150 km due to EUV
photons Lower peak at 110 km due to X-rays Lower
peak is very variable, often absent
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How might flares affect GPS or communications? D
o terrestrial empirical models of
secondary ionization work at Mars? Can response
of neutral atmosphere and ionosphere to
changes in solar flux be decoupled?
Mendillo et al., Science, 24 Feb 2006
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Meteors
Does Mars have seasonal meteor showers? If so,
what are the sources? Does Mars ever
experience massive meteor storms? How do meteors
affect atmospheric chemistry? What can we learn
about the atmospheric structure from these test
particles?
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Weird Stuff
What ionospheric irregularities and instabilities
are present? Equatorial spread-F? Equatorial
electrojet? What is the equivalent of the
dynamo current system? Can ionospheric currents
induce magnetic fields as large as the planets
internal field?
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Available Observations and Models

• Thousands of Ne(h) profiles
• New topside ionospheric sounder (MARSIS)
• Particles and fields measurements
• 1-D model of ionospheric photochemistry and
  diffusion
• MHD models for Mars environment exist
• Apply CISM tools to Mars?

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Sources of images
http//science.nasa.gov/ssl/pad/sppb/edu/magnetosp
here/images/mag_sketch.gif http//www.windows.ucar
.edu/earth/images/earth_magneto.jpg http//mgs-mag
er.gsfc.nasa.gov/publications/grl_28_connerney/grl
_28_connerney_fig1.html http//www.nature.com/natu
re/journal/v435/n7043/images/nature03603-f1.2.jpg
http//www.spaceweather.com/aurora/images/31mar01/
haug1.jpg http//sirius.bu.edu/data/flare_effect_j
pg.jpg