Plasma column position

Adapted version of InnerStabilisation.ipynb by Daniela Kropáčková, Honza Stöckel and Vojtěch Svoboda.

This notebook loads Mirnov coil data and calculates the plasma column position from them.

Import libraries

In [1]:
import os

#delete files from the previous discharge
if os.path.exists('icon-fig.png'):
    os.remove('icon-fig.png')

import numpy as np
import matplotlib.pyplot as plt
import holoviews as hv
hv.extension('bokeh')
import hvplot.pandas
from scipy import integrate, signal, interpolate
import pandas as pd
import requests
from IPython.display import Markdown

Set discharge number

To calculate the plasma position, $B_t$ contribution must be subtracted from the Mirnov coil signal. This contribution can be acquired by two ways: from a dedicated vacuum shot with the same toroidal magnetic field, or it can be estimated from the standard diagnostics. If a suitable vacuum shot is available, its number is stored in the variable vacuum_shot. If it isn't available, the vacuum_shot variable shall be set to False and the $B_t$ contribution shall be estimated.

In [2]:
# data_URL = "http://golem.fjfi.cvut.cz/shots/{shot_no}/DASs/LimiterMirnovCoils/{identifier}.csv"  #Mirnov coils and quadrupole
BDdata_URL = "http://golem.fjfi.cvut.cz/shots/{shot_no}/Diagnostics/BasicDiagnostics/{identifier}.csv" #BD = basic diagnostic
# data_URL = "http://golem.fjfi.cvut.cz/shots/{shot_no}/DASs/022Daniela0InnerStabilization/{identifier}.csv"  
data_URL = "http://golem.fjfi.cvut.cz/shots/{shot_no}/Diagnostics/LimiterMirnovCoils/DAS_raw_data_dir/Nidatap_6133.lvm" #NI Standart (DAS)

from urllib.request import urlopen

def get_file(url, shot, silent=False):
    URL = 'http://golem.fjfi.cvut.cz/shots/%i/%s' % (shot, url)
    if not silent:
        print(URL)
    f = urlopen(URL)
    try:
        return np.loadtxt(f)
    except ValueError: # the data couldn't be converted to a row of numbers
        print('The data could not be read! Using default values.')
        return np.array([35022])

shot_no = 35805
#shot_no = 35021
vacuum_shot = int(get_file('/Diagnostics/LimiterMirnovCoils/Parameters/vacuum_shot', 0))
#vacuum_shot = 35022 #number of the vacuum shot or 'False'
print('Vacuum shot: %i' % vacuum_shot)

ds = np.DataSource(destpath='')  
http://golem.fjfi.cvut.cz/shots/0//Diagnostics/LimiterMirnovCoils/Parameters/vacuum_shot
Vacuum shot: 35785

Data access

In [3]:
def open_remote(shot_no, identifier, url_template=data_URL):
    return ds.open(url_template.format(shot_no=shot_no, identifier=identifier))

def read_signal(shot_no, identifier, url = data_URL, data_type='csv'): 
    file = open_remote(shot_no, identifier, url)
    if data_type == 'lvm':
        channels = ['Time', 'mc1', 'mc5', 'mc9', 'mc13', '5', 'RogQuadr', '7', '8', '9', '10', '11', '12']
        return pd.read_table(file, sep = '\t', names=channels)
    else:
        return pd.read_csv(file, names=['Time', identifier],
                     index_col = 'Time', squeeze=True)

def get_basic_diag_data(shot):
    url = ( 'http://golem.fjfi.cvut.cz/shots/{}/Diagnostics/BasicDiagnostics/'
            'basig_diagnostics_processed.csv'.format(shot) )
    print(url)
    return pd.read_csv(url, header=0, index_col='Time')

Mirnov coil signal processing: integration and $B_t$ elimination

Load the data of a given Mirnov coil, integrate it and subtract the $B_t$ contribution from them.

In [4]:
def elimination (shot_no, identifier, vacuum_shot = False):
    #load data 
    mc = (read_signal(shot_no, identifier, data_URL, 'lvm'))
    mc = mc.set_index('Time')
    mc = mc.replace([np.inf, -np.inf, np.nan], value = 0)
    mc = mc[identifier]
    
    konst = 1/(3.8e-03)

    if vacuum_shot == False: 
        signal_start = mc.index[0]
        length = len(mc)
        basic_diag = get_basic_diag_data(shot_no)
        Bt = basic_diag['Bt']
        if len(Bt)>len(mc):
            Bt = Bt.iloc[:length]            
        if len(Bt)<len(mc):
            mc = mc.iloc[:len(Bt)]
        
        if identifier == 'mc1':
            k=300
        elif identifier == 'mc5':
            k= 14
        elif identifier == 'mc9':
            k = 31
        elif identifier == 'mc13':
            k = -100 
        
        mc_vacuum = Bt/k
    else:
        mc_vacuum = (read_signal(vacuum_shot, identifier, data_URL, 'lvm'))
        mc_vacuum = mc_vacuum.set_index('Time')
        mc_vacuum = mc_vacuum[identifier]
        mc_vacuum -= mc_vacuum.loc[:0.9e-3].mean()    #remove offset
        mc_vacuum = mc_vacuum.replace([np.inf, -np.inf], value = 0)
        
        mc_vacuum = pd.Series(integrate.cumtrapz(mc_vacuum, x=mc_vacuum.index, initial=0) * konst,
                    index=mc_vacuum.index*1000, name= identifier)    #integration

    mc -= mc.loc[:0.9e-3].mean()  #remove offset
       
    mc = pd.Series(integrate.cumtrapz(mc, x=mc.index, initial=0) * konst,
                    index=mc.index*1000, name= identifier)    #integration
    
    #Bt elimination
    mc_vacuum = np.array(mc_vacuum) 
    mc_elim = mc - mc_vacuum
    
    return mc_elim

Find plasma start and end

In [5]:
plasma_start = float(get_file('Diagnostics/BasicDiagnostics/Results/t_plasma_start', shot_no))
plasma_end = float(get_file('Diagnostics/BasicDiagnostics/Results/t_plasma_end', shot_no))

print ('Plasma start =', round(plasma_start, 3), 'ms')
print ('Plasma end =', round(plasma_end, 3), 'ms')
http://golem.fjfi.cvut.cz/shots/35805/Diagnostics/BasicDiagnostics/Results/t_plasma_start
http://golem.fjfi.cvut.cz/shots/35805/Diagnostics/BasicDiagnostics/Results/t_plasma_end
Plasma start = 3.654 ms
Plasma end = 18.747 ms

Horizontal plasma position $\Delta r$ calculation

In [6]:
def horpol(shot_no, vacuum_shot=False):
    mc1 = elimination(shot_no, 'mc1', vacuum_shot)
    mc9 = elimination (shot_no, 'mc9', vacuum_shot)
    
    b = 93
    
    r = ((mc1-mc9)/(mc1+mc9))*b
    r = r.replace([np.nan], value = 0)
    return r.loc[plasma_start:plasma_end]

r = horpol(shot_no, vacuum_shot)
ax = r.plot()
ax.set(ylim=(-85,85), xlim=(plasma_start,plasma_end), xlabel= 'Time [ms]', ylabel = '$\Delta$r [mm]',
       title = 'Horizontal plasma position #{}'.format(shot_no))
ax.axhline(y=0, color='k', ls='--', lw=1, alpha=0.4)
Out[6]:
<matplotlib.lines.Line2D at 0x7f6e34324c10>

Vertical plasma position $\Delta z$ calculation

In [7]:
def vertpol(shot_no, vacuum_shot = False):
    mc5 = elimination(shot_no, 'mc5', vacuum_shot)
    mc13 = elimination (shot_no, 'mc13', vacuum_shot)
    
    b = 93
    
    z = ((mc5-mc13)/(mc5+mc13))*b
    z = z.replace([np.nan], value = 0)
    return z.loc[plasma_start:plasma_end]

z = vertpol (shot_no, vacuum_shot)
ax = z.plot()
ax.set(ylim=(-85, 85), xlim=(plasma_start,plasma_end), xlabel= 'Time [ms]', ylabel = '$\Delta$z [mm]', title = 'Vertical plasma position #{}'.format(shot_no))
ax.axhline(y=0, color='k', ls='--', lw=1, alpha=0.4)
Out[7]:
<matplotlib.lines.Line2D at 0x7f6e21e1e210>

Plasma column radius $a$ calculation

In [8]:
def plasma_radius(shot_no, vacuum_shot=False):
    r = horpol(shot_no, vacuum_shot) 
    z = vertpol(shot_no, vacuum_shot) 
    
    a0 = 85
    a = a0 - np.sqrt((r**2)+(z**2)) 
    a = a.replace([np.nan], value = 0)
    return a.loc[plasma_start:plasma_end]


a = plasma_radius(shot_no,vacuum_shot)
ax = a.plot()
ax.set(ylim=(0,85), xlim=(plasma_start,plasma_end), xlabel= 'Time [ms]', ylabel = '$a$ [mm]',
        title = 'Plasma column radius #{}'.format(shot_no))
Out[8]:
[(0, 85),
 Text(0, 0.5, '$a$ [mm]'),
 (3.654, 18.747),
 Text(0.5, 0, 'Time [ms]'),
 Text(0.5, 1.0, 'Plasma column radius #35805')]

Save the results

In [9]:
plasma_time = []
t = 0
for i in a:
    if i>85 or i <0:
        a = a.replace(i, value = 0)
    else:

        plasma_time.append(a.index[t])

    t+=1
start = plasma_time[0]-1e-03 
end = plasma_time[-1]-1e-03 
print('start =', round(start, 3), 'ms')
print('end =', round(end, 3), 'ms')
start = 3.653 ms
end = 18.737 ms
In [10]:
r_cut = r.loc[start:end]
a_cut = a.loc[start:end]
z_cut = z.loc[start:end]
df_processed = pd.concat(
    [r_cut.rename('r'), z_cut.rename('z'), a_cut.rename('a')], axis= 'columns')
df_processed
Out[10]:
r z a
Time
3.654 13.206666 30.754832 51.529480
3.655 13.090738 30.585856 51.730465
3.656 12.985339 30.515975 51.836108
3.657 12.836744 30.352655 52.044490
3.658 12.694697 30.191093 52.248551
... ... ... ...
18.732 -70.617913 -17.137323 12.332418
18.733 -70.613707 -19.135230 11.839542
18.734 -74.365451 -25.422563 6.409116
18.735 -74.506372 -26.382883 5.960415
18.736 -72.465245 -28.499799 7.131840

15083 rows × 3 columns

In [11]:
savedata = 'plasma_position.csv'
df_processed.to_csv(savedata)

Markdown("[Plasma position data - $r, z, a$ ](./{})".format(savedata))

Plot the results

In [12]:
hline = hv.HLine(0)
hline.opts(
    color='k', 
    line_dash='dashed',
    alpha = 0.4,
    line_width=1.0)

layout = hv.Layout([df_processed[v].hvplot.line(
    xlabel='', ylabel=l,ylim=(-85,85), xlim=(start,end),legend=False, title='', grid=True, group_label=v)
                    for (v, l) in [('r', ' r [mm]'), ('z', 'z [mm]'), ('a', 'a [mm]')] ])*hline

plot=layout.cols(1).opts(hv.opts.Curve(width=600, height=200),  
                    hv.opts.Curve('a', xlabel='time [ms]'))
plot
Out[12]:
In [13]:
responsestab = requests.get("http://golem.fjfi.cvut.cz/shots/%i/Production/Parameters/PowSup4InnerStab"%shot_no)
stab = responsestab.text

if '-1' in stab or 'Not Found' in stab:
    fig, axs = plt.subplots(3, 1, sharex=True, dpi=200)
    r.plot(grid=True, ax=axs[0])
    z.plot(grid=True, ax=axs[1])
    a.plot(grid=True, ax=axs[2])
    axs[2].set(ylim=(0,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$a$ [mm]')
    axs[1].set(ylim=(-85,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$\Delta$z [mm]')
    axs[0].set(ylim=(-85,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$\Delta$r [mm]', title = 'Horizontal, vertical plasma position and radius #{}'.format(shot_no))

else:
    fig, axs = plt.subplots(4, 1, sharex=True, dpi=200)
    dataNI = (read_signal(shot_no, 'Rog', data_URL, 'lvm')) #data from NI
    dataNI = dataNI.set_index('Time')
    dataNI = dataNI.set_index(dataNI.index*1e3)
    Irog = dataNI['RogQuadr']
#     Irog=abs(Irog)
    Irog*=1/5e-3
    r.plot(grid=True, ax=axs[0])
    z.plot(grid=True, ax=axs[1])
    a.plot(grid=True, ax=axs[2])
    Irog.plot(grid=True, ax=axs[3])
    axs[3].set(xlim=(start,end), ylabel = 'I [A]')
    axs[2].set(ylim=(0,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$a$ [mm]')
    axs[1].set(ylim=(-85,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$\Delta$z [mm]')
    axs[0].set(ylim=(-85,85), xlim=(start,end), xlabel= 'Time [ms]', ylabel = '$\Delta$r [mm]', title = 'Horizontal, vertical plasma position and radius #{}'.format(shot_no))


plt.savefig('icon-fig')