Meeting Update 02.07

Presentations
The LLE presentation is at:
​http://www.pas.rochester.edu/~shuleli/magclumps2.pdf

Clumps

The beta map of a bx case, vs a by case.
http://www.pas.rochester.edu/~shuleli/clumpstudynew/bxbybeta.png
We can see there is a wake of low beta, low density region hiding behind the clump in the bx case. However, clump material is totally exposed to the erosion of the shock.
In the by case, there is a cylindrical cavity filled with strong magnetic field (low beta) surrounding the clump's "tail". Clump material are partly protected by this field. The field covering the boundary flow region is amplified by stretching. There is also an amplification region at the head of the clump initially, due to compression. Stretching is more effective in amplifying the field in this scenario. This is partly why the contained field case does not do much in terms of evolution. The only working field amplification mechanism is the compression by the transmitted shock, which is slowed down by a factor of 10.

The following shows the comparison of by cases between resistive and nonresistive runs at approximately 1 crushing time. The resistivity is isotropic and constant. We have microphysical resistivity which depends on the number density and the temperature, and nonlinear. We may want to try that out later.
http://www.pas.rochester.edu/~shuleli/clumpstudynew/cloudcrushingresistive.png
We can see some blueish region disappeared, and the region behind transmitted shock has a higher beta. The clump tail is less obvious in the resistive case. The field diffusion speed is 2 orders of magnitudes smaller comparing to the shock speed. We can expect things getting more different when the resistivity is higher. Then again the problem is "is the realistic microphysical resistivity high enough to trigger noticeable effect".

The high res runs (50 zones per radius) have been sitting on the bluegene queue for five days.
It's currently near the top of the queue. The three queued jobs are bx strog, by weak, by strong respectively. Hopefully we can finish these plus the "single mode" contained field case within this month. Since these runs need to have a ending time twice as the AAS runs (we need at least 4 crushing time), I expect at least 48 hours on 512 processes for each run.

Multiphysics

Flux limited thermal conduction. Saw strange behavior while doing the test on the Parrish&Stone paper. Switched to the simple "ring test", found that the inner boundaries are doing some strange things when run in parallel. See the following picture.
http://www.pas.rochester.edu/~shuleli/clumpstudynew/fluxlimiteddiff.png

Future Meetings, Abstracts?

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