Status of the Diagnostics Development for the Stellarator

Max-Planck-Institute for Plasma Physics
Status of the Diagnostics Development for the Stellarator Wendelstein 7-X
R. König1, W. Biel2, C. Biedermann1, R. Burhenn1, G. Cseh4, M. Endler1, T. Estrada5, O. Grulke1, D. Hathiramani1, M.Hirsch1, M. Jakubowski1, G. Kocsis4, P. Kornejew1, A.
Krämer-Flecken2, M. Krychowiak1, M. Laux1, A. Lorenz1, O. Neubauer2, M. Otte, 1E. Pasch1, B. Plaum6, T. Sunn Pedersen1, O. Schmitz2, B. Schweer2, T. Szepesi4, H.
Thomsen1, T. Windisch1, S. Wolf7, D. Zhang1, S. Zoletnik4
1Max-Planck-Institute
for Plasma Physics, D-17491 Greifswald, Germany, 2Institute of Energy- and Climate Research, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany, 3Princeton Plasma Physics Laboratory, Princeton, New Jersey
08543, USA, 4Wigner RCP RMI, H-1121 Budapest, Konkoly Thege 29-33, Hungary, 5Laboratorio Nacional de Fusi´on, CIEMAT para Fusi´on, Madrid, Spain, 6IGVP Univ. Stuttgart ,Pfaffenwaldring 31, 70569 Stuttgart, Germany
Thomson Scattering Diagnostic
Flux Surface Measurements
Lasers 5 (2) (Q-switch, Nd-YAG, 2 J)
Spatial
p
channels: up
p to 60 ((10))
20 eV < Te < 10 keV,
5·10
5
1018 m-3 < ne< 5
5·10
1020 m-3
Δreff ≈ 2.5 cm,
laser freq.: 20 Hz.
Obs. optic: N.A. 0.37, f/1.3, 7 lenses, Ø160
mm, f=172 mm, ~23 kg (lenses), 20-200°C,
lens system housing: Titanium
Complete measurement
i HM51/10
in
Partial measurement
i HM21/30
in
2D-positioning of
fluorescence rods,
each equipped
q pp
with an e-gun
(repeatability of
~1mm)
Q
Quartz
fibres: rectangular
g
on p
plasma side 1.1 x 3.2 mm2 consisting
g of separate
p
bundles of differing length (delay line), optic side Ø 3 mm
Polychromators
W7-AS
3D field line tracing
Fluorescent
rodd
ƒ Two interleaving push rods (outer & inner tube) for axial movement
(outer) and rotation (inner) in combination with slide bearings to fully scan
the plane in the triangular plasma vessel cross section
ƒ 4 reference points provided in heat shield tiles
via metal coated optical fibres
Δt = 10-30s
e-beam
Electron beam in background gas
(~450m approx. 12 revolutions)
2D Poincaré plot
−Outer tube: axial movement 1550mm,
v ≈ 10mm/s, repeatability: ±0.5mm
−Inner tube: axial movement120mm Æ
Δα=160°, v ≈ 1mm/s, repeatability : ±0.05mm
Polychromator filter curves
silicon avalanche diode detectors
utilizing moveable fluorescent
rod, 4 reference points
Water cooled shutter
Dispersion Interferometer
Reflectometry Systems
Steering Doppler Reflectometer
Corner Cube
Reflector (CCR)
Irrradiation angle / °
32 elements phased array beam steering by changing the freq.
Î no movable parts, fast scan of Bragg angle electronically
Doppler Reflectometry
K-spectrometer:
measures
changes in
turbulence
amplitude and
propagation
velocity for
selected K and r
Phase shift due to the plasma:
e2
λ2
⋅
⋅ ne L
2 ⋅ 4π 2 c 2 ε 0 me
2
2
(
)
e
2
π
λ
2
2ω:
⋅
⋅
⋅n L
λ 2 2 ⋅ 4π 2 c 2 ε 0 m e e
ω:
2π
λ
⋅
ω
Δϕ p = 2Δϕ p − Δϕ p
2ω
3
e2
= λ⋅
⋅ ne L
2 4πc2ε 0me
Frequency / GHz
fixed angle 18o Î ~1cm structures
50 GH
GHz - 110 GH
GHz, x/o-mode
/
d
optimized spot diameter:
2*w0=50mm @80 GHz (λ=3.75mm) ~sqrt( λ )
W7-X single chan. interferometer
Poloidal Correlation Reflectometry
P. Rohmann, et al., IEEE
International Symposium on
Phased Array Systems &
Technology, p. 559 (2013)
CCR
- Stack of thin Al and Cu sheets
- Stack covered by galvanic Cu
- Al sheets etched away
−turbulence characteristics
(correlation length) around the
separatrix
−poloidal propagation velocity
Î ExB velocity
Î separatrix position from Er=0
Î “quasi coherent”-mode?
Î magnetic
g
ppitch ((aimingg at jBS)
Interferometer and Thomson scattering laser
beams are using the same pair of ports
hopping reflectometer system, Ka-band
1 launch, 4 receiving antennas
-> 5 waveguides 10mm x 10mm -> max. length ~10m -> rack in torus hall
10 Simplified IR/vis. Divertor Observation Systems for OP1
2 Long Pulse Compatible IR/vis. Endoscopes for OP1.2 (10 for OP2)
Toroidally directed AEQ Port
3 observation windows
protected by uncooled
rotating shutter:
Camera transport system
Actual view with
EDICAM from AEQ21
J-port
Diamagnetic Loops (all 3 loops installed)
Compensation loops
only in triangular plane
measure the toroidal magnetic flux
measure the toroidal magnetic flux due
to the magnetic field coils
cancelled
plasma
1.5 µm < λ < 13 µm Î solutions still
need to be developed:
Water cooled
cold aperture
IR camera
3-5 µm
outer vessel flange
115 x 60 wide angle endoscope
Design and manufacturing by ©Thales SESO
Optical design frozen:
IR spatial resolution with 40% MTF
6 mm most of the target area
10 mm near edges
Investigation of Transparent Single-Walled Carbon Nanotube Coatings
SW-CNTs produced by IWS Fraunhofer (Dresden,
L. Hu et al, Appl. Phys.
Germany)
y) and by
y Nanolab were tested:
L tt 94,
94 081103 2009
Lett.
el. conductivity of IWS SW-CNTs ~10-80x higher
(varies with surface density)
IWS SW-CNTs: 1.5% ECRH transmission would
require: 3g/m2 (factor 100 higher than in
publication)) resulting
p
g in 3-5 Ω Î IR transmission
@ 2.5 µm: 3.5% & 3-5 µm: 1.5%
Î IR Transmission much lower than expected!
λ = 3 – 5 µm
“Quality“ of SW-CNTs obviously important
λ = 2 mm Detectors attached to endoscopes are not affected by ECRH Next steps: K. Kamaras at KFKI
stray radiation due to ECRH absorber (Al2O3/TiO2) coated
B d
Budapest
t (use
(
doped
d d materials?)
t i l ?) ,
cold
ld apertures, divergence
di
behind
b hi d last
l mirror
i
(-120x),
(
) losses
l
in windows & lenses (~20%) Î 0.02µW/pxl. ~ 0.01K/s
Unidym Inc.
Multi-purpose Manipulator, Therm. He-beam, Divertor Langmuir
Probes and Visible Spectroscopy
Target integrated Langmuir probes
D
Downstream
ne & Te
T
optical unit
Visible
spectroscopy
& tomography
L-port
tiltable solid angle of observation
He-beam HM51
Ionization, dissociation,
impurity concentration, ne & Te
optical unit
J-port
Limiter
Langmuir
g
probes
(only in
OP1.1)
divertor
gas nozzles
Rogowski Coils (all 5 coil systems installed)
Mirnov Coils (all 124 for OP1 manufactured, ~50% installed)
measure the total toroidal electric
current and moments
ECRH stray rad. protection
Observation of MHD modes
and magnetic fluctuations:
Frequency range: 1 kHz - 1 MHz
124 installed for OP1.1
44 to be installed for OP2
Location → outside
and inside the plasma
vessel
Fast reciprocating
Langmuir probe
HM11
Upstream Γio, v||,
ne, Te, DC &
turbulent time scale
In-board
limiter
in OP1.1
Visible
Spectroscopy
& Tomography
Ionization, dissociation,
impurity concentration,
ne & Te
Segmented
Rogowski coils →
measure the poloidal
distribution of the
toroidal electric current
promising
i i publication:
bli ti
L Hu
L.
H et al,
l
Appl. Phys. Lett. 94, 081103 2009
L. Hu et al, Appl. Phys.
Lett. 94, 081103 2009
UV/Vis./IR endoscope (250 nm – 5 µm)
2 UV and 3 vis. CCD & 1 IR
camera covering 70x70 mm
area with 0.5
0 5 mm resolution
+ fibre optics to high & low
resolution spectrometers per
endoscope with front
sweeping mirror
Module 51 system looks at
He-beam gas injection system
(UV/)vis. spectral range Î ITO
(successfully tested at IPP
R. König et al., Rev. Sci. Instr. Xxx)
visible
camera
0.4-0.8 µm
Viewing and scanning geometry
2 endoscope pairs covering
- upper divertor module 51
- lower divertor module 30
L-port
ECRH Stray Radiation Protection of Windows
Transparent conductive coatings
Minimisation of mirror contamination by
ƒ observation through small pinhole (entrance pupil Ø=6mm)
ƒ hydrogen gas flow through pinhole
ƒ uncooled shutter closed between discharges
ƒ first mirror heatable to 350 C for overnight/weekend cleaning
ƒ shutter integrated ceramic heater for relative calibration of IR and
visible channels
The cameras with wide angle optics are
mounted directly behind the windows:
1 IR micro-bolometer camera
2 visible light cameras with interference
filters for Hα, Hγ, C II, C III
Cameras were tested in 2.5T magnetic field
Endoscopes for Tomographic Observation of Line Emission from the Divertor
Main loops:
Compensation loops:
pinhole
port protection
10 observation systems
are monitoring each of
the 10 discrete divertors
Pinhole optics +
relay optics +
PCO PixelFly CCD
or image guide
spectroscopy, illumination
etc.
quartz air
vacuum
vacuum
vacuum
shutter
Video camera view
Pinhole optics +
EDICAM (CMOS)
water cooled
front head
Water cooled
front plate
sap
pphire
10 Toroidally Viewing Video Camera Systems
P1
P6
P5
P7
B//
He-beam HM30
P2
P3
P4
BN+ZrO2
Bθ
Downstream Multiple array Langmuir probes (LP)(5 tips)
Magnetic
coils
(MC)
(2 x 6 connectors)
ne & Te
Mach probe (MP) (2 tips)
LP:
P1Æ vf1 (floating potential)
P2 Æ Isat (negative biased)
P3 Æ v3 (positive biased)
P4 Æ vf4 (floating potential)
therm. He-beam
box with
gas bo
t 5
piezo valves
MP:
P6 Æ Isat (negative biased)
P7 Æ Isat (negative biased)
MC:
Two sets of coils at
different radial
position;
Bt; Bθ; Br
fluctuations
Arrangement of the multi-purpose manipulator at port AEK40
Folded loop
made of
continuous
ribbon
ibb cable
bl
fits through
large ports for
installation
In-vessel
assembly
test without
ECRH stray
radiation
shield
High Efficiency Extreme Ultraviolet Overview Spectrometer (HEXOS)
- impurity release and transport Spectral survey instrument:
Channel 1: 2
2.5
5 – 10.5
10 5 nm
Channel 2: 9 – 24 nm
Channel 3: 20 – 66 nm
Channel 4: 50 – 160 nm
Outer vessel Cryostat
High Efficiency Extreme Ultraviolet Overview Spectrometer (HEXOS)
Bolometer
Wavelength and absolute calibration with:
coating
screen
Kock-source
Spark-source
- system successfully operated on
TEXTOR for several years
- now installed on W7-X
Tube support
Exchange chamber
Linear drives
plasma
Fraunhofer-Institute
Aachen
Gate valves
Inner vessel
Calibration:
A. Greiche et al,
RSI 79, 093504
(2008)
HEXOS No. 1
detectors
Horizontal camera Vertical camera
HEXOS No. 2
Vertical camera: front end
HEXOS No.
N 4
Design criteria
ƒ Front plate active cooling
required for steady-state
operation:
p
thermal loads up
p
to 100 kW/m2
ƒ Factor 300 microwave stray
radiation reduction by
damping & screening
water cooled aperture
clamp ring
HEXOS No.
N 3
detector holder
microwave shield
Port AEK40
Vacuum systems