Alcator C-Mod Thomson scatering diagnostics


1. Thomson scattering viewing geometry

2. Details of edge Thomson scattering viewing geometry

3. Thomson scattering data in ELECTRONS tree:

Central temperature vs time - \thom_midpln:te_t
Central density vs time - \thom_midpln:ne_t

4. Data from new 8 channel core Thomson scattering (starting from 2002)

5. Data from old 6 channel core Thomson scattering

6. Data from edge Thomson scattering

7. H-mode pedestal parameters (from tanh fit of edge TS data)

a) New core Thomson scattering system - nodes in \ELECTRONS::TOP.YAG_NEW, tag \YAG_NEW
 
Node Description Units
calib:z_nom 1D array of Z coordinates of scattering volumes along laser beam as a function of spectrometer number.
Z=0 - geometrical midplane
m
calib:theta 1D array of scattering angles (deg) deg
results.spect_X:ne_t 1D array of ne vs time from a given spectrometer
X - spectrometer number from 1 to 8
m-3
results.spect_X:ne_err Density errors, same dimensions as above m-3
results.spect_X:te_t 1D array of Te vs time
X - spectrometer number from 1 to 8
keV
results.spect_X:te_err Temperature errors, same dimensions as above keV
results.spect_X:r_mid_t 1D array of midplane radius (m) vs time as mapped by EFIT
X - spectrometer number from 1 to 8
m
results.profiles:ne_rz 2D array of ne(t,rmid). 
0 dimension - time(s)
1 dimension - z (m) sorted in descending order
m-3
results.profiles:ne_err Density errors, same dimensions as above m-3
results.profiles:te_rz 2D array of Te(t,rmid). 
0 dimension - time(s)
1 dimension - z (m) sorted in descending order
keV
results.profiles:te_err Temperature errors, same dimensions as above keV
results.profiles:r_mid_t 2D array of midplane radius as mapped by EFIT. 
To look at  ne profile at a given time t0 plot ne(t0,*) vs rmid(t0,*)
m

Top

b) Old core Thomson scattering system - nodes in \ELECTRONS::TOP.YAG.RESULTS
 
Node Description Units
PARAM:N_SPECT Number of working spectrometers
PARAM:R Major radius of laser beam m
PARAM:NAMES_Z 1D array of spectrometers names (letters B, D, ...) vs Z of scattering volumes
DETAILS.CHORD_X:NE_T 1D array of ne vs time from a given spectrometer
X - spectrometer letter (see above)
DETAILS.CHORD_X:NE_ERR Density errors, same dimensions as above m-3
DETAILS.CHORD_X:TE_T 1D array of Te vs time
X - spectrometer letter (see above)
keV
DETAILS.CHORD_X:TE_ERR Temperature errors, same dimensions as above keV
DETAILS.CHORD_X:R_MID_T 1D array of midplane radius (m) vs time as mapped by EFIT
X - spectrometer letter
m
GLOBAL.PROFILE:NE_RZ_T 2D array of ne(t,rmid). 
0 dimension - time(s)
1 dimension - z (m) sorted in descending order
m-3
GLOBAL.PROFILE:NE_ERR_ZT Density errors, same dimensions as above m-3
GLOBAL.PROFILE:TE_RZ_T 2D array of Te(t,rmid). 
0 dimension - time(s)
1 dimension - z (m) sorted in descending order
keV
GLOBAL.PROFILE:TE_ERR_ZT Temperature errors, same dimensions as above keV
GLOBAL.PROFILE:R_MID_T 2D array of midplane radius as mapped by EFIT. 
To look at  ne profile at a given time t0 plot ne(t0,*) vs rmid(t0,*)
m

Top

b) Edge Thomson scattering system - tags in ELECTRONS tree
 
Tag Description Units
\TS_NE 2D array of ne(t,rmid).  m-3
\TS_NE_ERR Density errors, same dimensions as above m-3
\TS_TE 2D array of Te(t,rmid).  eV
\TS_TE_ERR Temperature errors, same dimensions as above eV
\TS_PE 2D array of electron pressure Pe(t,rmid) eV*m-3
TS_PE_ERR Pressure errors eV*m-3
\TS_RMID 2D array of midplane radius as mapped by EFIT. 
To look at  ne profile at a given time t0 plot ne(t0,*) vs rmid(t0,*)
m

Top

c)Pedestal parameters:

Replace X in the table below  with NE, TE, or PE to look at density, temperature, or pressure pedestal parameters

Note: Pedestal parameters' time base is not the same as the TS data time base - only the points with well converged tanh fit are included.
 
Tag Description
\X_95 Value at Y95 flux surface vs time
\X_SEP Value on the separatrix vs time
\X_B Pedestal baseline vs time
\X_HEIGHT Pedestal height vs time
\X_WIDTH Pedestal width (mm) vs time
\X_POS_ABS Pedestal position vs time (midpoint position on the midplane) (m)
\X_GRAD Maximum pedestal gradient vs time

Top