Contribution in physics data base on ELM control by RMPs

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


• 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


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.


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


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)


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


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


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


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


Ambient turbulence in H-mode


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


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


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


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


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


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


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


H-mode + RMP


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)


-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”


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


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]


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


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.


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

Contribution in physics data base on ELM control by RMPs

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