[Question] Shaped active coils

[konerr]

Hi,

Is it possible to define active coils are shaped coils as in FreeGS? I see that polygons are only available for passive structures and the description of the DIIID machine in freegs4e only consists of the coil centroids unlike that in FreeGS which uses ShapedCoils.

Thanks,
Rahul

[georgeholt1]

Hi @konerr

Thanks for the question. FreeGS4E also contains the ShapedCoil class so you may be able to use this in the same way as in FreeGS. Unfortunately we have not tested this in FreeGSNKE workflows yet so it is possible that issues will arise. I'd be very grateful if you could report the success or failure of your case if you do try it.

[konerr]

Hi @georgeholt1,

ShapedCoil class works fine as long as I am using the freegs4e module. With FreeGSNKE, there is no mechanism to recognize this class to build a machine. It only uses the MultiCoil and Circuit from freegs4e. Maybe there is a way to combine ShapedCoil with the existing machinery of FreeGSNKE, but I am not sure how to do it without adding this feature in build_machine.py.
I have created a minimal example for you to try.

import numpy as np
import freegs4e
from freegs4e.shaped_coil import ShapedCoil
from freegs4e.machine import Wall

active_coils = []

## DIIID machine description from FreeGS
coils = [ ("FC1",ShapedCoil([[1.6042, -1.64455], [1.7736, -1.64455], [1.7736, -1.51145], [1.6042, -1.51145]])) ]

R = np.array([1.016,1.016,1.016,1.016,1.016])
Z = np.array([ 0.00000e+00,9.64000e-01,9.68000e-01,1.00100e+00,1.01900e+00])
wall = Wall(R,Z)

limiter = []
for r,z in zip(R,Z):
limiter.append({"R":r, "Z":z})

## This works since ShapedCoils is defined in freegs4e
tokamak1 = freegs4e.machine.Machine(coils, wall=wall)

## This throws an error since shaped coils is not recognized in
## active_coils
from freegsnke import build_machine
tokamak2 = build_machine.tokamak(active_coils_data=coils,
limiter_data=limiter)
#wall_data=[])