Coupling the RCM to LFM

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Coupling the RCM to LFM

• Frank Toffoletto (Rice)
• and
• John Lyon (Dartmouth)

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RCM - LFM Coupling

• This is the result of a prelimimary test on
  one-way coupling
• We have used 1 MHD snapshot to provide input data
  to the RCM
• RCM uses MHD computed magnetic field (for flux
  tube volumes), pressure and density
• Pressure and density are used to estimate
  temperature
• These variables in turn are used to populate the
  initial distribution function

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The RCM equations

• The RCM advects each fluid by solving

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Coupling process

• LFM data is interpolated onto a regular grid
• This allows for reasonably fast calculations when
  computing such RCM variables as flux tube volume
• The ionospheric electric field for these runs is
  not taken from the MHD

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Mapped RCM grid (equatorial plane) using LFM
Magnetic field
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RCM pressure
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RCM Computed ion temperatures
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Results

• After 4hours R-2 currents form leading to some
  shielding of the electric field
• Pressure in the inner magnetosphere starts to
  symmetrize as particles gradient and curvature
  drift
• Channels of low content flux tubes low pVg flux
  tubes being squirted into the inner magnetosphere

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Next Step

• Incorporate MHD computed potential boundary
  conditions and conductivities
• Use a time-sequence of MHD inputs to do a more
  realistic run

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Final Comment

• This was a test to see how the RCM would react to
  MHD input data
• Two way coupling is a ways off, but some of the
  computational machinery is in place and just
  needs to be turned out
• Exchange will be with data files