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ORNL-Fusion / aorsa

All ORders Spectral Algorithm (The Original)
MIT License
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ntilda calculation may need to be rechecked. #12

Open cornwalllau opened 4 years ago

cornwalllau commented 4 years ago

Ntilda calculation from Fred below:

"From the continuity equation, one would think that ntilda should look like div(Je) which would be noisier than E itself. But in looking at it more closely, I see that Naoto and I did not calculate it by taking numerical derivatives of Je, precisely because it was too noisy. Instead, we got it directly from velocity space integrals of f1 which is linear in E, but has a bunch of sums over Bessel functions and Z functions (Z0, Z1 and Z2) in it. Off hand, I don't see where delta0 enters, but maybe the Z functions are noisy, especially if we str using the new fancy ones. I don't remember what we were doing for the Z functions."

Fred.

AreWeDreaming commented 4 years ago

Sorry for the wrong comment. The last line was commented where ntilda is set to finite differences is commented out, I missed that.