Collaboration fuses codes for efficient simulation

(Page 2 of 3)

“There were two sets of scales that had to be resolved,” says Phillip Colella, leader of the Berkeley group.  One was the huge plasma cloud; the other was the tiny pellet that converts to ionized gas.

“You can’t afford to use a uniform grid to resolve that small scale,” Colella says.  “On the other hand, you need to resolve that small scale or you aren’t going to get the right answer.”

Adapt to survive

Samtaney developed algorithms modeling magnetohydrodynamics (MHD) – the interaction of magnetic fields with electrically conducting fluids, like plasmas.  His codes depict how streaming electrons heat the tiny frozen fuel pellet.

He turned to Adaptive Mesh Refinement (AMR) to make those algorithms practical on a simulation the size of ITER.  AMR conserves computer resources by focusing data points in the most interesting areas – around the pellet – and putting fewer points elsewhere.

Colella’s group has created a library of AMR algorithms called Chombo.  With support from DOE’s Scientific Discovery through Advanced Computing (SciDAC) program, Samtaney worked with Brian Van Straalen in Colella’s group to adapt Chombo’s mesh algorithms for his simulation.

The result: The fusion refueling simulation ran several hundred times faster than it would have with a uniform mesh.

« Previous       1   |   2   |   3   |   Print       Next »