Inverse solve failing for ITER example

[georgeholt1]

In example 8 - static_inverse_solve_ITER, the notebook fails during the inverse solve. I have observed two failure modes:

1. During inverse solve iterations, a RuntimeError is encountered, which causes execution to hang indefinitely.
2. The solver fails to converge, or reports convergence prematurely, resulting in an undesirable equilibrium.

For 1., output reads:

[freegs4e/jtor.py:361]: RuntimeWarning: divide by zero encountered in scalar divide
  L = self.Ip [/](https://file+.vscode-resource.vscode-cdn.net/) I_R - LBeta0 * (IR [/](https://file+.vscode-resource.vscode-cdn.net/) I_R - 1)

For 2., this is an example of a "successful" equilibrium:

The final message from the solver was:

Inverse static solve SUCCESS. Tolerance 8.99e-05 (vs. requested 0.0001) reached in 62/100 iterations.

[kpentland]

Just a comment that we're looking into this!