NSTX-U MHD Instability Diagnostic Measurement
Capabilities – January 2015
(black – available
for experiments, blue – under active development)
|
Physics
Measurement
|
Typical range
and coverage
|
Spatial;
Temporal Resolution
|
Typical
Precision
|
Available
Diagnostic Techniques
|
Comment
|
Contact
|
Low (m,n) MHD modes, sawteeth, locked modes, and disruption precursors
|
DB/B = 10-4 – 10-1,
(0,0)<(m,n) < (5,10)
|
2 MHz
|
|
Mirnov coils outside plasma, known as the “high-n” array
|
12 toroidal
|
E. Fredrickson, S. P. Gerhardt - PPPL
|
|
n=1,2&3 RWM Detection
|
|
Toroidal
arrays of BP and BR sensors inside the vessel.
|
Used for both n=1 RWM feedback and Dynamic Error
Field Correction, and offline analysis
|
C. Myers-PPPL
|
|
5 cm; < 300kHz bw
|
|
Filtered
poloidal SXR arrays
|
2 arrays (32 ch); discrete AXUV diode arrays
|
K. Tritz, J. M. Burgos – JHU
|
|
1
cm, < 10 kHz
|
5%
(rel)
|
Tangential
multi-color SXR arrays
|
5 color/ 20 spatial channels, AXUV diode arrays
|
K. Tritz, J. M. Burgos – JHU
|
>2x1011 cm-2
|
4MHz
|
2x1011
cm-2
|
Tangential
interferometry, polarimetry (FIReTIP)
|
FIR laser with retroreflector in 1 tangential
chord at RTAN=0.64 m
|
C. Domier – UC Davis, Y. Ren - PPPL
|
Cut-off
1.1-7.0 x1013cm-3
|
2.5 MHz BW
Dr ~ 1cm
|
|
Quadrature reflectometer
(MHD density fluctuation)
|
30-75 GHz, 16 channels
|
S. Kubota - UCLA
|
|
250 kHz
|
|
Neutron scintillator array
|
Plastic scintillators with PM tubes 1-
ZnS; 3 BC400
|
D. Darrow - PPPL
|
High frequency instabilities (MHD, fast ion modes)
|
DB/B ≥ 10-3 to 10-7,
n
= 0 – 30
|
5 MHz
|
Toroidal
and poloidal
|
Mirnov
coils outside plasma, known as the “high-f” array
|
3-BT in toroidal array, and 8-BP in Toroidal array,
4-BP in poloidal array
|
E. Fredrickson – PPPL
|
|
5 cm; < 300kHz BW
|
|
Filtered
poloidal SXR arrays
|
2 horizontal arrays (32 ch); discrete AXUV diode
arrays
|
K. Tritz, J. M. Burgos – JHU
|
1.1-7.0 x1013cm-3
|
2.5 MHz BW
|
|
Quadrature reflectometer
|
30-75 GHz, 16 channels
|
S. Kubota - UCLA
|
>2x1011 cm-2
|
500 kHz
|
2x1011 cm-2
|
Tangential interferometry, polarimetry (FIReTIP)
|
FIR laser with retroreflector in 1
tangential chord
|
C. Domier – UC Davis, Y. Ren - PPPL
|
Magnetic field pitch angle fluctuations
|
|
3 cm core, 2 cm edge, 5 ms
|
>0.2°
|
Motional Stark effect based on collisionally-induced-
fluorescence (MSE/CIF)
|
18 channels implemented,
presently applies correction for toroidal rotation, requires heating beam
source A.
|
Y. Sechrest, F. Levinton – Nova Photonics
|
Disruption Halo Currents
|
0-1000 A
|
~10x~20cm tiles, 0.1 msec resolution
|
|
Shunt Tile Arrays
|
10 tiles in outboard divertor and 18
on center column
|
S.P. Gerhardt, PPPL
|