update

Ran a series of tests on the BE module. I found that I can get a stable sphere when running on my old data files, with the current version of astrobear I had been using; there was an issue with my data files. I then found I could get a stable sphere when running my current data files but at a lower resolution and smaller box size. This narrowed down the change in the data files to resolution/box size causing the instability. I am now trying to rule out what causes the instability (i.e. a larger box or a higher resolution or the combo of the the 2..?). It seems that perhaps the larger box in which the sphere sits may be throwing it out of equilibrium? Perhaps the BE solution can withstand only so much material outside of the sphere that is out of equilibrium…

Also, of possible interest.. in the runs that were collapsing (but that shouldn't have been…) The set up was initially in hydrostatic equilibrium, but seemed to remain in equilibrium throughout the collapse… ?? I made the vector plots of acceleration of (-gradP-gradPhi)/rho and saw vectors in the ambient pointing inwards (the gravitational acceleration), but inside the sphere all vectors canceled out — i.e. the forces balanced out inside the sphere. This behavior remained the same as the collapse happened. This is contrary to what I would think should happen. In the event of collapse, the inward gravitational acc vectors should dominate inside of the sphere. Something to perhaps look into at another time..

Sorry, likely won't be able to post movies or figures this week with homework, but will try to have a concrete diagnosis of what went wrong before…

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