contribution in physics data base on elm control by rmps
DESCRIPTION
Reflectometry study on turbulence and ELM dynamics in limiter H–mode plasmas with and without RMP in TEXTOR. S. Soldatov 1 , A. Krämer-Flecken 2 , M. Yu. Kantor 2,3,4 , B. Unterberg 2 , G. Van Oost 1 , D. Reiter 2 and TEXTOR team - PowerPoint PPT PresentationTRANSCRIPT
Mit
glie
d d
er
Helm
holt
z-G
em
ein
sch
aft Reflectometry study on turbulence and ELM
dynamics in limiter H–mode plasmas with and without RMP in TEXTOR.
S. Soldatov1, A. Krämer-Flecken2, M. Yu. Kantor2,3,4, B. Unterberg2, G. Van Oost1, D. Reiter2 and TEXTOR team
1 Department of Applied Physics, Ghent University, Ghent, Belgium 2 Institut für Energieforschung - Plasmaphysik, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Jülich, Germany 3 FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein, The Netherlands, www.rijnhuizen.nl 4 Ioffe Institute, RAS, Saint Petersburg 194021, Russia
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
• Contribution in physics data base on ELM control by RMPs
• Tuning of RMP control schemes to meet ITER requirements
• TEXTOR features:
Dynamic Ergodic Divertor => RMP m/n=3/1, 6/2, 12/4 (AC or
DC) High Resolution Multi-Pass Thompson Scattering (10kHz,
r=1cm)
Correlation ReflectometryCorrelation Reflectometry (2MHz, 0.8<r/a<0.95, T (2MHz, 0.8<r/a<0.95, TFreqStepFreqStep>50ms)>50ms)
Beam Emission Spectroscopy (on Li-beam, meas. ne, vpol)
MOTIVATION
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
• Scheme of experiments
• Limiter H-mode w/o RMP
- Plasmas parameters
- Ambient turbulence (AT) and coherent modes
- Rotation
• Limiter H-mode with RMP
- Effect on the pedestal and ELMs
- How influenced AT and coherent modes
- Rotation
• Conclusions
Plan
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
bc
de
bc,de=0.025 radcd= 0.05 radbd,ce=0.075 radbe= 0.1 rad
rcutoff
Two O-mode heterodyne reflectometersf0= 2637 GHz and 2640 GHznc= 0.841.70 and 0.841.98 ·1019m-3
Scheme of experiment
=5.75
Antennae array provides 4 probing areas and 4 distances in poloidal direction.It is a good bases for investigation of turbulence spatial-temporal properties.The reliability of velocity measurements increases.
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
K.H. Finken et al., Nucl. Fus. 47 (2007), 522.B. Unterberg et al., 34th EPS Conference on Plasma Phys. 2007, P-2.053
Limiter H-mode scenario in TEXTOR
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
Limiter H-mode scenario with NBI co injection
0 1 2 3 4 5 6 70
0.10.2
I P /
MA
0 1 2 3 4 5 6 70
1
2
Pto
t / M
W
0 1 2 3 4 5 6 70123
x 1019
ne
/ m
-3
0 1 2 3 4 5 6 70
5
D/
a.u
.
0 1 2 3 4 5 6 70
5
D/
a.u
.
time / s
107310
107315
BT = 1.3 T, qa = 3.7, R = 1.72 m, a = 0.44 m •Reduced Bt (≤1.9T), plasma limited by inner wall
•power threshold 1.6-2.0 MW at 1.3T
•Confinement improvement <40%
•High frequency ELMs (300-1300 Hz)
B. Unterberg, 16th European Fusion Physics Workshop, Cork, Ireland, 1-3 December 2009K.H. Finken et al., Nucl. Fus. 47 (2007), 522.B. Unterberg et al., 34th EPS Conference on Plasma Phys. 2007, P-2.053
Ip=235 kA, Bt=1.3 T, R=1.72 m, a=0.44 m (qa=3.7), Ptot=1.6 MW (NBI co-current)
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.450
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
TEXTOR. #107308. HRMP Tompson Scattering. t=[2.003;2.0048]s.
z [m]
Nor
mal
ized
to m
ax
Plasma profiles dynamics (High Resolution Multi-Pass TS).
Pedestal mostly manifests itself in density.
TEXTOR. #107308. High Resolution TS. Electron Density
z [m
]
2.001 2.002 2.003 2.004 2.005 2.006 2.007
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
2.001 2.002 2.003 2.004 2.005 2.006 2.007
1.8
2
2.2
2.4
x 104
t [s]
NNee
TTee
ppee
Between ELMs
DD
Reflectometer covers 0.8<<0.95
1 1.5 2 2.5
-0.5
0
0.5
y
TEXTOR # 107308, t= 2.5 s
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
Turbulence spectrum trough L-H transition .
cc=41.5 cm=41.5 cmcc=40 cm=40 cm
cc=39 cm=39 cmcc=37.8 cm=37.8 cm
OhmicOhmicHH
NBI co
Quasi coherent mode at f~13kHz is observed after L-H transitionQuasi coherent mode at f~13kHz is observed after L-H transition.
No mode in L-mode phase.
HHLL
Radial scan of ~ 4 cm
N23
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QC modes of 48 ,110 kHz and 13kHz are located inside c=41.5 cm. Poloidal m numbers from CR data are estimated (assuming RBR):
13kHz<=> m~5, 48kHz<=>m~19, 110kHz<=>m~43 Two last agree with peripheral HF coherent mode on C-Mod in EDA [Hubbard PoP2001]
-400 -200 0 200 400
1E-8
1E-7
1E-6
1E-5
c=41.5 cm, f
0=28.0 GHz
c=40.0 cm, f
0=32.0 GHz
c=39.0 cm, f
0=34.5 GHz
c=38.0 cm, f
0=37.0 GHz
Am
plitu
de [a
.u.]
Frequency [kHz]
TEXTOR. #107307. Reflectometry. 1.75<t<4.0 s
-40 -20 0 20 401E-6
1E-5
1E-4
Frequency [kHz]
6.00.510)216(
105.122223
3
fr
m
m~19
m~43
m~5
Spectrum overview vs radius (in Between ELMs).
38 39 40 41 42
0.0
0.5
1.0
"13 kHz" mode 110 kHz 48 kHz
Nor
mal
ized
z [cm]
Modes amplitudeModes amplitude
m~5
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
32 34 36 38 40 42 44
-20
-10
0
10
20
L-mode
IDD
EDD
[k
rad/
s]
pol
[cm]
NBI1
TEXTOR. Reflectometry. #107307-107335. (04.03.2008), I=230, B=1.3, n_e~2
H-mode, no DED
Turbulence rotation. L and H mode.
NBI1 imparts the co-current toroidal momentum that results in the NBI1 imparts the co-current toroidal momentum that results in the directed directed
in IDD direction (helicity Btin IDD direction (helicity Bt↑↓Ip ↑↓Ip ).). Rotation shear s= dv/dr ~12.0 E+512.0 E+5 s-1 at =42 cm
Turb. decorrelation rate dc= 2.52.55 E+55 E+5 s-1 at =42 cm.
The rotation shear
limiter
ss > > dcdc
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
Ambient turbulence in H-mode
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2.000 2.001 2.002 2.003 2.004 2.005 2.006 2.007 2.008
500
400
300
200
100
0
TEXTOR. Reflectometry. #107308. B=1.3, I=230, <n>=2. Turbulence Spectrogram.
D
The turbulence spectrum modulated in accordance with ELM events.
Spectrum broadens during the ELM crash and shrinks in between ones.
Integral level varies by several times.
Refl. spectrum evolution on ELM time scale
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2.002 2.004 2.0060.0
0.2
0.4
0.6
0.8
1.0
1.2
36
38
40
42
44Phase
E /S
QR
T(L
n)
t [s]
D
TEXTOR. #107308. Reflectometer (B)
c [cm
]
Recovery period contains Silent StageSilent Stage when n/n drops below Ohmic level and increasesincreases indicating pedestal formation.
↑↑, ccconstconst => => => => => => => => ne decreases at >c.
Turbulence level increase before ELM (like for ELMs type I)
c
Detailed analysis of turbulence level
80<f<500kHz.Ln factor accounted very accurate owing to HRTS data
n
E
L
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2035 2036 2037 2038 2039 2040 2041 2042
0
0.2
0.4
0.6
0.8
1TEXTOR.' #107308(b)
Am
pl.
, a.
u.
2000.5 2001 2001.5 2002 2002.5 2003 2003.5 2004 2004.5 2005 2005.5
-2
0
2
Pha
se ,
rad
2000.5 2001 2001.5 2002 2002.5 2003 2003.5 2004 2004.5 2005 2005.50
0.5
1
1.5
2
Time, ms
RM
S o
f ph
ase
, ra
d
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2080 2081 2082 2083 2084 20850
0.5
1
TEXTOR.' #107308(b)
Am
pl.
, a.
u.
2080 2081 2082 2083 2084 2085
-2
0
2
4
Pha
se ,
rad
2080 2081 2082 2083 2084 20850
0.5
1
1.5
Time, ms
RM
S o
f ph
ase
, ra
d
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2200 2201 2202 2203 2204 2205 2206 2207 22080
0.2
0.4
0.6
0.8
1
TEXTOR.' #107308(b)
Am
pl.
, a.
u.
2200 2201 2202 2203 2204 2205 2206 2207 2208-4
-2
0
2
Pha
se ,
rad
2200 2201 2202 2203 2204 2205 2206 2207 22080
0.5
1
1.5
2
Time, ms
RM
S o
f ph
ase
, ra
d
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2048 2049 2050 2051 2052 2053 2054 20550
0.2
0.4
0.6
0.8
1
TEXTOR.' #107308(b)
Am
pl.
, a.
u.
2048 2049 2050 2051 2052 2053 2054 2055-4
-2
0
2
Pha
se ,
rad
2048 2049 2050 2051 2052 2053 2054 2055
0
0.5
1
1.5
2
Time, ms
RM
S o
f ph
ase
, ra
d
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
2078 2079 2080 2081 2082 2083 2084 20850
0.2
0.4
0.6
0.8
1
TEXTOR.' #107308(b)
Am
pl.
, a.
u.
2078 2079 2080 2081 2082 2083 2084 2085-4
-2
0
2
Pha
se ,
rad
2078 2079 2080 2081 2082 2083 2084 20850
0.5
1
1.5
Time, ms
RM
S o
f ph
ase
, ra
d
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
H-mode + RMP
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
Pedestal degrades with RMP amplitude
ELM =360 Hz
ELM =560 Hz
ELM = 700 Hz
0
5
0
5
0
5
0
5
2.36 2.38 2.40
5
time / s
D/ a.u.
107308 (H-mode)
107310 (L-mode)
107318 (DED 1.0 kA)
107321 (DED 2.5 kA)
107322 (DED 4.0 kA)
c,
min
107318, 1.0 kA
107321, 2.5 kA
0.85 0.9 0.95 1 1.05N
L
107322, 4.0 kA
Reduction of D ELM burst
B. Unterberg et al., PSI Conference 2008B. Unterberg, 16th European Fusion Physics Workshop, Cork, Ireland, 1-3 December 2009
0.34 0.36 0.38 0.40 0.42 0.440
200
400
600
800
1000 #107307, L-mode 107308, H-mode + 0 kA DED 107318, H-mode + 1.0 kA DED 107323, H-mode + 3.25 kA DED 107323, H-mode + 4.0 kA DED
p e [P
a]
z [m]
TEXTOR. HRMP Thompson Scattering. Electron Pressure.
Effect from RMP application
DED coils layout
with RMP amplitude:
pedestal degrades
ELM ampl. decreases
ELM increases
The features are the same as observed on diverter machines (JET, DIIID)
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
-500 -400 -300 -200 -100 0 100 200 300 400 500
10-4
10-3
Frequency [kHz]
Pow
er [
a.u.
]
TEXTOR. Reflectometry. Fourier power spectra for inter ELM stage. nfft=2048
107332, IDED
=3.75 kA
107328, IDED
=3.25 kA
107320, IDED
=2.5 kA
107319, IDED
=1.5 kA
107318, IDED
=1.0 kA
107329, IDED
=0 kA
-20 -10 0 10 20
c~0.83
-30 -20 -10 0 10 20 301
1.5
2
2.5
3
3.5
4
4.5
5x 10
-3
Frequency [kHz]
Pow
er [
a.u.
]
TEXTOR. Reflectometry. Fourier power spectra for inter ELM stage. nfft=2048
107332, IDED
=3.75 kA
107328, IDED
=3.25 kA
107320, IDED
=2.5 kA
107319, IDED
=1.5 kA
107318, IDED
=1.0 kA
107329, IDED
=0 kA
c~0.83
QC modes both at 13 and 48 and 110 kHz die away when RMP amplitude increases.
The turbulence spectral integral increases with IDED by ~2 times within 1<IDED<3.75 kA.
Spectral characteristics (r=37cm, r/a=0.83)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.50.0
0.5
1.0
1.5
2.0
2.5
0.00
0.05
0.10
0.15
0.20
0.25
0.98
1.15
0.50
Am
plitu
de [a
.u.]
DED current [kA]
QC 13 kHz
0.67
QC 120 kHz
Spect_Integr. 25-500 kHz
“13 kHz”
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
TEXTOR. #107307, MC Pi000, df=0.488kHz, dt=1.024ms, nfft=2048, ADC
=1us, Ovlp=50%.
t [s]
Fre
quen
cy [
Hz]
2 2.5 3 3.5 40
1
2
3
4
5
6x 10
4
Da BumpLim
-40 -20 0 20 400.0
0.5
1.0
1.5
2.0
Mirnov Coils Pi030
t=1.8-2.05 s
# 107307Reflectometer rc=41.5 cm
Frequency [kHz]-40 -20 0 20 40
0.0
0.5
1.0
1.5
2.0
# 107307Reflectometer rc=37.9 cm
Mirnov Coils Pi030
Frequency [kHz]
t=3.55-4.0 s
MC see broader peak 10<f<17 kHz than Reflectometer.
There were not found a direct correlation between MC and Reflectometer data.
The explanation – ”multiple variable mix” of several modes like EHO observed in DIIID.
[K.Burrell et al, PoP2001]
N8
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
0 1 2 3 4 5 6 7 8
x 10-3
0
10
20
30
40
50
60
70
80
90#107307. ELMs period distribution. 1.8 <t< 2.7 s
t [s]
PD
FT
ELM ~2 ms
2.227 2.228 2.229 2.23 2.231 2.232 2.233
-4
-3
-2
-1
0
1
2
3
4
t [s]
#107307. Mirnov Coils Pi075. BPF [11.5;15] kHz. Nspline=5, nbx=1
-5 -4 -3 -2 -1 0 1 2 3 4 5
x 10-3
0
10
20
30
40
50
60
t [s]
PD
F
#107307 Pi000#107307 Pi075Averaged
Pre Post
Time lag between ELM crash and burst in Magnetics signal (11.5 <f< 15.0 kHz)
-150s
+1300s
TELM
D
MC
Magnetic fluctuations were studied on the pre @ post cursor subject in #107307.
In the view of not regular response in MC statistical analysis was implemented within 1.8<t<2.7 s <=> ~400 ELM crashes. <TELM>~2ms
Two clear peaks: Pre cursor (~-150us) and Post cursor (~1300 us)
Precursor is more localized (FWHMis more localized (FWHMPrePre=150us)=150us)
means more regularmeans more regular compare with Postcursor but less representative (N/Ntot~27%)
Post cursor is distributed broader: FWHMPost=500us,
and more representative: N/Ntot~40% Most likely that the rest of magnetic bursts (~40%) Most likely that the rest of magnetic bursts (~40%)
are not related with the ELMs.are not related with the ELMs. Deep within 0<Deep within 0<t<0.7 ms => nearly no magnetic t<0.7 ms => nearly no magnetic
fluctuations in the beginning of recovery stage fluctuations in the beginning of recovery stage
<TELM> <TELM><TELM>~2ms
Analysis of 13kHz mode in magnetic fluctuations.
Data for 2 poloidal probes 0o and 75o
agrees well.
t [s]
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
32 34 36 38 40 42 44
-20
-10
0
10
20
L-mode
IDD
EDD
[k
rad/
s]
pol
[cm]
NBI1
TEXTOR. Reflectometry. #107307-107335. (04.03.2008), I=230, B=1.3, n_e~2
H-mode, no DED
H-mode, DED 1 kA
H-mode, DED 2.5 kA
H-mode, DED 3.25-3.75 kA
H-mode, DED 5 kA
Turbulence rotation. RMP influence.
RMP reduces the rotation shear at periphery of H-mode plasmas.
It agrees with pressure profile deterioration observed with TS
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
Conclusions Limiter H-mode in TEXTOR is characterized by the following:
1) 13 kHz mode (5<m<6) is found both in Correlation Reflectometer (CR) and MC data manifests the properties of precursor mode (like for type III ELMs). It is located several cm inside the separatrix very close to pedestal region. It disappears gradually with pedestal degradation. No correlation found between CR and MC data (”multiple variable mix” ?). Similar to EHO mode studied at DIIID.
2) QC oscillation with m~19 and 43 were identified also inside separatrix. Their frequency and radial location agree with QC mode observed at C-Mod.
2) The significant shear of plasma perpendicular rotation is found around the pedestal.
3) Turbulence level at pedestal evolves by several times according to ELM activity. Inside the recovery period the Silent StageSilent Stage was found which is characterized by extremely low turbulence level and grow of probing wave phase. 4) In most cases turbulence level increases before ELM crash as usually observed for type I ELMs.
In H-mode plasmas the turbulence rotation exhibits strong shear near pedestal region which exceeds the decorrelation time of AT.
RMP application decreases the rotation shear in H-mode plasmas and pedestal quality. RMP leads to increase of the turbulence level in the mean and all coherent modes die away.
IRW9 Lisbon 4-7 July 2009 S. Soldatov Ghent University
37
38
39
40
41
42
43
1600 1800 2000 2200 2400 2600 2800 3000 3200 3400-60
-40
-20
0
20
40
60
L
DED=2.5kA
H
t [s]
Y A
xis
Titl
e
L
RcLn107321_rcutoffcm “13 kHz” QC mode degrades
with RMP amplitude.
DED 2.5kADED 2.5kA
Fre
qu
en
cy
[k
Hz]
Fre
qu
en
cy
[k
Hz]
Fre
qu
en
cy
[k
Hz]
Fre
qu
en
cy
[k
Hz]
Turbulence spectrum. Response on RMP .
c [cm]
c [cm]
30
32
34
36
38
40
42
1600 1800 2000 2200 2400 2600 2800 3000 3200 3400-60
-40
-20
0
20
40
60
LH
t [s]
L
c
DED 1kADED 1kA
Da
#107321
#107318