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A Comparative Examination of
Plasmoid Structure and Dynamics at
Mercury, Earth, Jupiter, and Saturn
James A. Slavin
Heliophysics Science Division
Greenbelt, MD 20771
www.nasa.gov
Planetary Magnetospheres
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What are Plasmoids and TCRs?
1.
Plasmoids are parcels of magnetospheric
plasma ejected down the tail by J x B,
pressure gradient and/or centrifugal
forces after their flux tubes are
reconfigured into flux ropes by
reconnection.
2.
The effects of Plasmoid formation and
ejection are felt over a large portion of
the tail as a result of lobe magnetic field
draping about the flux rope. These lobe
signatures are termed traveling
compression regions (TCRs) because
they move with the plasmoid.
3.
Many TCRs are observed for every
plasmoid due to their differing spatial
extents.
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Traveling Compression Region
(Slavin et al., GRL, 1984)
Why are Plasmoids Important?
1.
Magnetospheric convection is impossible without the loss of
plasma down the tail through Plasmoid ejection; without
plasmoids the flux tube contraction required to complete the
Dungey and Vasyliunas-type plasma circulation would be
stopped by adiabatic compression (Erickson-Wolf Effect).
2.
Plasmoid properties are a key source of information on the
reconnection process – reflecting the time of onset, properties
of the flux tubes that merge and the number, location, and
intensity of X-lines.
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Earth
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Plasmoid Evolution
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Ieda et al. (JGR, 1998)
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BBF-type and Plasmoid-type Flux Ropes
BBF-type Flux Ropes
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Plasmoid-type Flux Ropes
Dungey Cycle Loading - Unloading
Slavin et al. (1993)
Slavin (1998)
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Mercury
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Steady Southward IMF & Periodic Plasmoids at Mercury
Slavin et al. (Science, 2009)
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Tail Loading – Unloading & Plasmoid Ejection
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Tail Loading – Unloading & TCRs
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Mercury Plasmoid Duration
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Near0Mercury Neutral Line Locations
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Jupiter and Saturn
Earth
Jupiter and Saturn
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Periodic Plasmoids at Jupiter
Huang et al. (JGR, 2003)
(Kronberg et al., JGR, 2007)
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Saturn Plasmoids
Hill et al. (JGR, 2008)
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Jackman et al. (JGR, 2008)
Saturn Multiple Plasmoid Event
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MHD Simulations of Mercury Plasmoid Ejection
Mercury
Kidder et al., (JGR, 2009)
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MHD Simulations of Saturn Plasmoid Ejection
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Jia et al. (2010)
Assessment
1.
2.
3.
Plasmoids and TCRs need to be surveyed and
modeled at all Four Magnetospheres using similar
criteria with durations of seconds to hours.
Effect of Magnetic Flux Transfer (Dungey Cycle) and
Internal Mass Addition Rates (Vasyliunas Cycle) on
plasmoid topology and X-line location needs to be
determined and understood.
The effects of heavy ions and finite gyro-radius
effects on current sheet stability and reconnection
needs to be determined for Mercury, Saturn, and
Jupiter.
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