Location 1 PF coils don't work if there is no CS

[jonmaddock]

In GitLab by @pc6783 on Oct 28, 2021, 15:09

I got this email from a PROCESS user at PPPL:

Presently, if any type-1 coils are included in the PF coil model and there is no central solenoid current, the peakb subroutine in pfcoil.f90 will find a zero peak magnetic field at the location of the type-1 coils, which will subsequently cause an error when running them through the superconductor models (which don't work for a zero background field). This can be fixed by adjusting the logic in the series of if/else statements in peakb (lines 1489-1497 of pfcoil.f90 in the develop branch).