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Equilibrium Diagnostics

NSTX-U Equilibrium 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

Coil currents

0-130 kA

follow pulse shape.

1.0%

Rogowski coil on buswork; Hall effect transducers at power supplies

For EFIT/LRDFIT equilibrium reconstruction

S. Gerhardt – PPPL

Plasma current, Ip,

0-2 MA

2-5 kHz sampling rate

1.0%

2 Rogowski coils around plasma outside vacuum vessel

For EFIT/LRDFIT reconstruction

 

S. Gerhardt – PPPL

Equilibrium Poloidal Field and Flux

 

Variable spatial resolution

 2-5 kHz sampling rate

1-3%

2D and 3D solenoids (Mirnov coils) inside vv, flux loops inside and outside vv

For EFIT/LRDFIT reconstruction

 

S. P. Gerhardt-PPPL

Plasma Equilibrium Reconstruction

 

10 mm absolute

 1 ms

 

Solutions of the Grad-Shafranov Equation Constrained by Measurements

Between shot analysis with the EFIT code; post-experiment analysis with EFIT and LRDFIT

 

S. Sabbagh – CU, J. Menard-PPPL

Plasma kinetic energy

> 10 kJ

1 ms

1 kJ

Diamagnetic loop

EFIT/LRDFIT constraint, uses TF coil

S. Gerhardt - PPPL

B field pitch (for determination of q(R) using LRDFIT or EFIT)

 

3 cm core, 2 cm edge, 10 ms (target 5 ms)

≥ 0.2°

Motional Stark effect based on collisionally-induced- fluorescence (MSE/CIF)

18 channels, presently applies correction for toroidal rotation, requires heating beam source A.

H. Yuh, F. Levinton – Nova Photonics

 

target - 3 cm core, 2 cm edge, 10 ms

target ≥ 0.2°

Motional Stark effect based on laser-induced-fluorescence (MSE/LIF) using DNB

10 channels, Requires compact, radial DNB

Y. Sechrest, F. Levinton – Nova Photonics

 

TBD (probably ~2 MHz)

 

1 mm radial polarimeter

Provides line integral constraint, in conjunction  with electron density profile input

S. Kubota - UCLA

Compact array of microwave receiving antennas. Two antennas can be configured to launch microwaves for imaging reflectometry.

Measures plasma emission up to 40 GHz with sub-millisecond time resolution.

 

Synthetic Aperture Microwave Imaging (SAMI)

Measures EBW emission as a function of poloidal and toroidal angle, allowing high radial resolution measurements of edge magnetic field pitch. Also can be configured for imaging relectometry to measure edge plasma flows.

G. Taylor – PPPL

R. Vann – University of York, UK

B field magnitude, P(R)

 

5 cm core, 2 cm edge, 10 ms

>5 Gauss

Motional Stark effect based on laser-induced-fluorescence (MSE/LIF) using DNB

10 channels, Requires compact, radial DNB

Y. Sechrest, F. Levinton – Nova Photonics