Notebook

Manual Matching of a WEST ICRH Antenna on Plasma¶

This notebook calculates the charts used in the internal documentation for the IC Operators for the manual matching on plasma.

In [ ]:

import matplotlib.pyplot as plt
import numpy as np
from tqdm.notebook import tqdm
import skrf as rf

# WEST ICRH Antenna package
import sys; sys.path.append('..')
from west_ic_antenna import WestIcrhAntenna
#rf.stylely()

Capacitance Diff vs Coupling Resitance¶

For a given RF frequency $f_0$ and phase setup, an antenna is generally first matched on vacuum conditions, leading to a couple of solution (C1, C2, C3, C4).

For the WEST preset frequencies, We create multiple plasma scenarios for low to high coupling cases and for each of them we determine the best matching point:

In [ ]:

# WEST Antenna matched on vacuum condition in dipole (default) for a given frequency
f0_MHzs = [55.5, 57] # [48, 53, 55.5, 57, 63]
delta_Cs = {}

for f0_MHz in tqdm(f0_MHzs):
    freq = rf.Frequency(f0_MHz, f0_MHz, npoints=1, unit='MHz')
    ant_vacuum = WestIcrhAntenna(frequency=freq)  # default is vacuum coupling
    Cs_vac = ant_vacuum.match_both_sides()
    
    Rcs = np.linspace(0.4, 1.7, num=10)
    Cs_plasmas = []
    
    for Rc in tqdm(Rcs):
        plasma = WestIcrhAntenna.interpolate_front_face(Rc, source='TOPICA-H-mode')
        ant_plasma = WestIcrhAntenna(frequency=freq, front_face=plasma)
        Cs_plasma = ant_plasma.match_both_sides()
        Cs_plasmas.append(Cs_plasma)
        
    delta_Cs[f0_MHz] = np.array(Cs_plasmas) - np.array(Cs_vac)

In [ ]:

fig, ax = plt.subplots()
for f0_MHz in tqdm(f0_MHzs):
    ax.plot(Rcs, abs(delta_Cs[f0_MHz][:,0] + delta_Cs[f0_MHz][:,2])/2, marker='^', label=f'{f0_MHz} MHz - Top')
    ax.plot(Rcs, abs(delta_Cs[f0_MHz][:,1] + delta_Cs[f0_MHz][:,3])/2, marker='v', label=f'{f0_MHz} MHz - Bot')
ax.set_xlabel('Coupling Resistance $R_c$ [Ohm]')
ax.set_ylabel('Capacitance Shift $\Delta C$ [pF]')
ax.set_title('Capacitance Shift to add from Vacuum Match Points (55 MHz)')
ax.legend()
ax.grid(True)