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3.3
Equilibrium Reconstruction using MSTFit
MSTFit is a 2D equilibrium reconstruction code which solves the Grad Shafranov
equation in a torus:
∆∗ ψ = −µ0 R2
dp
1 dF 2
−
dψ 2 dψ
Where
F (ψ) = RBφ
∂
∆ ψ=R
∂R
∗
1 ∂ψ
R ∂R
+
∂ 2ψ
∂Z 2
The plasma current, pressure, and reversal and pinch parameters are taken as
inputs, and a current profile is created from this input. If there are additional diagnostics such as MSE 22 or probe measurements, the data is compared to expected
values for the MSTFit generated equilibrium, and used in a χ2 minimization routine
to additionally constrain the fit. The pressure input is the straightforward product of
electron (from Thomson scattering) and ion temperature and density. A full write-up
of how MSTFit works is presented in Anderson’s thesis 23 .
DRAFT December 19, 2010