Di vertor P lasma S imulator II DiPS II 2 nd PMIF Workshop Sep 19 2011 Julich Germany HJ Woo 1 KS Chung 1 SJ Park 1 SG Cho 1 EK Park ID: 265754
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Slide1
Status of Divertor Plasma Simulator – II (DiPS-II)
2nd PMIF Workshop
Sep. 19, 2011Julich, Germany
H.-J. Woo
1
, K.-S. Chung
1
, S.-J. Park
1
,
S.-G. Cho
1
, E.-K. Park
1
, and T. Lho
2
1
Center for Edge Plasma Science,
Hanyang
University, Seoul 133-791, Korea
2
National Fusion Research Institute,
Daejeon
305-333, KoreaSlide2
CONTENTS Review of DiPS – I LaB6 Cathode
Concepts and Objects of DiPS – II
Summary and Future WorkSlide3
DiPS-I : Schematics
LaB
6 is located at null magnetic field. DiPS - ISlide4
Typical Magnetic Field of DiPS-IDiPS - ISlide5
Probe Diagnostics : I-V Characteristics vs. Magnetic Field
vs. Discharge CurrentDimensions of Probe Tip: 0.5 mm (Dia.) and 3 mm (length)
DiPS
– I : Experimental ResultsSlide6
Probe Diagnostics : Electron Temperature (Te) and Plasma Density (np)
vs. Magnetic Field vs. Discharge Current
Plasma Density : Confinement Effect
Plasma Density : Particle Flux Density
DiPS
– I : Experimental ResultsSlide7
LIF Diagnostics vs. Magnetic FieldIon Temperature
Drift Velocity Ion temperature and parallel flow velocity are increased versus the magnetic field intensity.
The perpendicular flow velocity remains near zero, since the contributions of E X B and diamagnetic effect are negligible at the plasma center in the magnetized cylindrical plasmas.DiPS – I : Experimental ResultsSlide8
LIF Diagnostics vs. Discharge CurrentIon Temperature
Drift Velocity Ion temperature and parallel flow velocity are increased versus the discharge current.
DiPS – I : Experimental ResultsSlide9
Ion Temperature and Drift Velocity vs. Plasma Density Magnetic Field Variation → Ion Temperature (Plasma Density + Magnetic Field) Discharge Current Variation → Ion Temperature (Plasma Density)
DiPS – I : Experimental ResultsSlide10
LaB6 Cathode for DiPS – I & II
LaB6 Cathode for DiPS
– I & IISlide11
LaB6 Cathode for MP2 – Large Plasma Source
LaB6 Cathode for Large Plasma GenerationSlide12
Heater Temperature EstimationLaB6 Cathode : Heater Temperature EstimationSlide13
B. Noyes, Jr., Phys. Rev. 24, 190 (1924). Heater Temperature Estimation
LaB6 Cathode : Heater Temperature EstimationSlide14
Objective of DiPS-IIUnderstanding of the Plasma Wall InteractionHigher Plasma Flow Generation with Magnetic Nozzle Concept.
Characterizations of Attached/Detached Plasmas (Neutral Effects). – Need Highly Differential PumpingDevelopments of Diagnostics for KSTAR.
Tests of PFC Materials.DiPS
- II
DiPS
– II has been developed to overcome the weaknesses of
DiPS
– I and improve the machine performance.
Weaknesses of
DiPS
– I:
Neutral Pressure Control – only two section separated by differential pumping.
Low Particle Flux – limited plasma current.
Small Plasma Size : Core Plasma Size ~ 2 cmSlide15
DiPS - IIB. Labambard, 21
st Transport Taskforce Workshop, Boulder, CO (March 25-28, 2008) .Slide16
Concepts of Magnetic Nozzle – From Helicon ExperimentsX. Sun, Phys. Rev. Lett. 95, 025004 (2005)
HELIX and LEIA, West Virginia University
Helicon Plasma Without Ion Heating VASIMR Concepts
DiPS
- IISlide17
Measurement Position A & B
Concepts of Magnetic Nozzle – From Experience of MP2 (NFRI: Dr. LHO)
DiPS - IISlide18
High Field Chamber (Position A): Magnetized
1st Port of Central Cell (Position B): Un-magnetized
Concepts of Magnetic Nozzle – From Experience of MP2 (NFRI: Dr. LHO)
DiPS
- IISlide19
Concepts of Magnetic Nozzle – From Experience of MP2 (NFRI: Dr. LHO)
High Field Chamber (Position A): Magnetized
1st Port of Central Cell (Position B): Un-magnetized
DiPS
- IISlide20
Schematic Diagram of DiPS-II
Magnetic Nozzle
DiPS - IISlide21
Typical Magnetic Field of DiPS-IIMagnet Power Supply
Magnet Label
Default Current
Sorensen
SGI
80- 125
M1
– M2
80 A (Max. 125 A)
Sorensen SGI 80 - 125
M3
– M4
60 A (Max. 125 A)
Sorensen SGI 40 – 250 (Parallel)
M5
– M6
450 A (Max. 500 A)
Sorensen SGI 200 – 125
M7 – M12
5
– 90 A
(Max. 125 A)
DiPS
- IISlide22
Diagnostics and Material Test Regime
First Plasma at Sep. 2010.
DiPS - II
Construction and Plasma GenerationSlide23
LaB6 Cathode Damage (Melting) at High Current Operation (over 90 A) In diverging field configuration, the LaB6 cathode can be damaged by localized current in light gas operation such as helium (low ion gyro-radius).
→ Need the Null Field Geometry
LaB6 Cathode Melting
DiPS
- IISlide24
DiPS – II : Flow Measurement Results The plasma flow velocity is nearly zero (stationary plasma), which might be due to grounded chamber wall disturbs the ion acceleration.Slide25
Install Laser Thomson Scattering for Detached Plasmas & Material Test
Mirror & Lens Array
TS Sample
Horizontal Pixel No. (related to Wavelength)
Vertical Pixel No. (related to Radial Position)
R = 0 mm
R = - 3.5 mm
R = +3.5 mm
R = -7 mm
R = +7 mm
R = +10.5 mm
R = +14 mm
R = -14 mm
R = -10.5 mm
Blocked Region (Rayleigh Scattering)
DiPS
– II: TS DiagnosticsSlide26
DiPS
– II: TS Diagnostics40 A Discharge with ArSlide27
Typical DivertorDiPS-1DiPS-2Pressure @ Source (mTorr)1 – 30
200 - 40020 - 50Pressure @
Transient (mTorr)-5
Pressure @
Diagnostics (
mTorr
)
1 - 30
1 - 10
0.1 – 100
Core
Plasma Size
~2 cm
~ 5 cm
Plasma Density (cm
-3
)
10
13
– 10
14
<10
14
@ near Source
~10
12
@ diagnostics
~10
13
@ Diagnostics
Electron Temperature (
eV
)
1-10
eV
2-3
eV
for
Ar
,
5-7
eV
for He
2-3
eV
for
Ar
,
5-7
eV
for He
Ion Temperature
T
i
~T
e
0.1
eV
for
Ar
0.1
eV
for
Ar
Particle Flux (m
-2
s
-1
)
~ 10
24
~10
22
10
22
-
10
24
Magnetic Field
~ 3 T
~ 1
kG
B
T
=3.5
kG
,
B
D
=1.5
kG
max.
Discharge Voltage
~
30 - 40 V for
Ar
~ 60 - 80 V for He
~
50-70 V for
Ar
~100 V for He
Discharge Current
50 A DC
150 A DC
SUMMARYSlide28
SUMMARYDiPS-1DiPS-2PLASMA DIAGNOSTICSPROBES
PROBESLASER-INDUCED FLUORESCENCELASER-INDUCED FLUORESCENCE
LASER THOMSON SCATTERINGETC
Small Size Ion
Beam
Source
will
be
Installed
for Material Damage TestSlide29
One will change magnetic nozzle chamber as floating structure (or biased structure), which is now grounding. One also add the source magnet for cusp magnetic field.The design is already finished.
FUTURE WORK