Transcript UCSD Program at NCSX J. Boedo for The UCSD and NCSX Teams

UCSD Program at NCSX
J. Boedo
for
The UCSD and NCSX Teams
J. Boedo, UCSD
Scanning Fast Probe
• General Information:
– Rotatable shaft (adjust to pitch angle)
– 10 tips (1xIsat, 2xDP, 2xImach, 4xVf (Er, E )
– Measures: Te, Ne (~3 ms), Isat, 2xEr, 2x
EMach #, Vpar , r, Vr, etc)
– Yet to be implemented (Fast Te)
– Bandwidth ~ 4 MHz
– DAQ Sampling 1MS/s
– In/out time ~ 80 ms
– Pedestal (-6 cm) penetration in lowish power
plasmas (2 MW)
• There is spare probe it PPPL!
– Head and shaft from exiting probe
– Needs new control system
– Use existing electronics box
– Can move some kepcos, ideally new ones
J. Boedo, UCSD
SFP: Fundamental Potential Contributions
•NSTX Physics we can test:
NCSX has low flow-damping >> Mach probe
Can manipulate flows for flow-shear stabilization. Can vary ripple to study:
Effects of flow damping >> Mach Probe
Zonal flows should be similar or larger than equiv. tokamak >> Measure Reynolds Stress
Designed to eliminate resonant field perturbations >> Ne, Te Vp structures
Designed for good flux surfaces at vacuum, intermediate and high  >> dito
High density operation
 Lower plasma edge temperature >> Measure
Greenwald limit impervious? >> Look at intermittency
MACH115523_1
0
Design PFCs >> Determine SOL/edge profiles
-0.2
•
DIII-D measurements during I-Coil experiments show:
– Potential increases (electron loss?)
– Shift in Isat (due to boundary being pushed or
pulled)
– Increase in Ne and Vr fluctuations (core density
drops)
– Te fluctuations drop!
High spatial resolution and dense measurements
important when geometry counts!
-0.4
Mach
•
Mach
-0.6
-0.8
-1
-1.2
-1.4
-2
0
2
4
6
J.Rrsep(cm)
Boedo, UCSD
8
Field Effects Require Fine Resolution
M125990_2
M125990_2
1500
0
Eth (V/m)
Eth (V/m)
-1000
-1500
500
-2000
-2500
0
222 224 226 228 230 232 234 236 238
60
125990 I-Coil
125990 no I-Coil
50
• Perturbation
at edge is
narrow
40
30
20
10
0
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Pos(cm)
Pos(cm)
M125990_2
M125990_2
700
700
125990 I-Coil
125990 no I-Coil
500
400
300
• Fluctuations
change
600
125990 I-Coil
125990 no I-Coil
500
Isatrms (A/cm2)
600
Isatrms (A/cm2)
Eth (V/m)
1000
Ethrms (V/m)
Ethrms (V/m)
Ethrms (V/m)
-500
• I-Coil
experiments
at DIII
70
Terms (eV)
500
400
300
200
200
100
100
0
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0
222 224 226 228 230 232 234 236 238
Pos(cm)
Pos(cm)
J. Boedo,
UCSD
Swinging Arm Probe
• Used in ASDEX and ALCATOR
• Proposed for DIII-D
• Very Compact, tucked in tiles
• Measurement capabilities (# tips, #
cables, complexity) depend on space
• Can be placed in divertor or wall
structures
Smick et al, JNM 2005
J. Boedo, UCSD
Limiter Probes/Calorimeters
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•
•
•
Modular system (instrumented tile) w probes and calorimeters
Rooftop probes. Brazed contacts
Staggered design for high spatial resolution
Crucial for PFC design and Heat/particle load evaluation
J. Boedo, UCSD
Fast Bolometer/SXR array
•Modular system, in vacuum
• Sensitive to radiated power over wide
energy range (1 eV - 10 keV) UV to
SXR. Filter wheel..remote!
• Fast time response (up to 2 MHz).
• Can be filtered to look at different
energy ranges
Fast total radiated power
30 channels on DIII-D estimate during disruption
•Multicolor system easy
•Relatively inexpensive ~$25k!
•Uses for NCSX:
•Plasma position
Shell inversion of emission during disruption (center post)
•Rough Te (breemstrahlung)
•Rough impurity monitor
•Plasma control?
Divertor ELM brightness
J. Boedo, UCSD
Fast Multi-Color Cameras
• Re-entrant optics w/ periscope for
tangential view OR Radial view
Movable Mirror
Lens
• Tangential or radial view imaging whole
plasma
– Two or more cameras w beam
splitters and filter wheels
– One camera with a rotating filter wheel
(air or belt)
•
Use He-I lines 668, 728, 706 nm for:
– Imaging plasma boundary
– Measuring ne, Te in the edge > Band
at the edge (puff some He)
– Other impurities (CI, CII, CIII) localize
radial region > impurity monitoring
– Plasma positioning
– Plasma wall contact
Periscope
Lens
Filter wheel
Camera 1
Beam splitter
Camera 2
J. Boedo, UCSD
Fast Multi-Color Cameras
12mm
objective
lens
Object
50mm
collimating
lens
Boronated polyethelyne
shielding box
Phantom 7.1
Camera
Fiber Bundle (2.73m)
Or periscope
50mm camera lens
Filter
Wheel
CMOS chip with 12 bit pixel depth. 1 pixel corresponds to ~0.4cm in vessel.
800x600 max spatial resolution.
Typically run at 256x256 res., with max possible frame rate of 26,000 sec-1.
Camera RAM = 2.8 GB (21,680 frames at 256x256).
Vacuum
window at 90R0
Inter-ELM image
CIII filter, f = 5000 sec-1, exposure = 180ms
ELM filaments
J. Boedo, UCSD
Movable Divertor Plates
• Pivoting point and only
change angle
• Two movable points
• Similar to movable limiters
in ALT-II collaboration
Vessel
• Wormscrew actuated from
outside (magnetically
connected feedthru)
Actuator
Pivot point
Divertor plate
J. Boedo, UCSD
Additional Slides
J. Boedo, UCSD
J. Boedo, UCSD
divertor
vacuum vessel
J. Boedo, UCSD