Coupling the RCM to LFM

Frank Toffoletto (Rice)

and

John Lyon (Dartmouth)

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

The RCM equations

• The RCM advects each fluid by solving:

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

Mapped RCM grid (equatorial plane)using LFM Magnetic field

RCM pressure

RCM Computed ion temperatures

QuickTime™ and aPNG decompressorare needed to see this picture.

QuickTime™ and aPNG decompressorare needed to see this picture.

QuickTime™ and aPNG decompressorare needed to see this picture.

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 pV flux tubes being squirted into the inner magnetosphere

Next Step

• Incorporate MHD computed potential boundary conditions and conductivities

• Use a time-sequence of MHD inputs to do a more realistic run

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