Forward calculaton

[kripnerl]

Hi,

I would like to ask whether there is a possibility of the forward calculation of plasma with a given profile from the coils.

I've tried something like this:

for name, coil in tokamak.coils: 
    coil.control=False
...
freegs_eq = freegs.Equilibrium(tokamak=tokamak, Rmin=eq.R_min, Rmax=eq.R_max, Zmin=eq.Z_min, Zmax=eq.Z_max, 
                               nx=Nx, ny=Ny, psi = grid.psi.T)
...
profiles = freegs.jtor.ConstrainPaxisIp(2.3e6, 2e6, eq.F0/mu_0)
...
freegs.solve(freegs_eq, profiles, psi_bndry=eq.lcfs.psi[0])

whereas a 'hint' I provide the Fiesta result (grid.psi.T). However this mock doesn't seem to be functional. Is there some similar functionality?

Thanks in advance,
Lukas

[bendudson]

In principle I think this should be possible, but it may be vertically unstable if a divertor geometry is being used: Each picard iteration the plasma may move towards one of the poloidal field coils. Perhaps adding a pair of poloidal field coils under feedback control might work?

Is the psi given to the Equilibrium constructor the total poloidal flux, or just due to the plasma? If you compare grid.psi.T to freegs_eq.psi() are they the same? It's a bit of a hack, but as a test you could try:

freegs_eq = freegs.Equilibrium(tokamak=tokamak, Rmin=eq.R_min, Rmax=eq.R_max, Zmin=eq.Z_min, Zmax=eq.Z_max, 
                               nx=Nx, ny=Ny, psi = grid.psi.T)

coil_psi = freegs_eq.psi() - freegs_eq.plasma_psi    # Flux due to coils
freegs_eq._updatePlasmaPsi(grid.psi.T - coil_psi)   # Set the plasma psi