Recent Results and Prospects for Correlation ECE ...Recent Results and Prospects for Correlation ECE...

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Recent Results and Prospects for Correlation ECE Measurements on TCV Correlation ECE Measurements on TCV L. Porte 1 , S. Coda 1 , T.P. Goodman 1 , A. Pocehlon 1 , V.S. Udintsev 2 , V. Vuille 1 1 Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EuratomConfédération Suisse, CH1015 Lausanne, Switzerland 2 ITER Organization, Building 519/122, CHD, Diagnostics Division Route de Vinon sur Verdon 13115 St Paul Lez Durance France 07/06/2012 17 th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating 1/17

Transcript of Recent Results and Prospects for Correlation ECE ...Recent Results and Prospects for Correlation ECE...

Page 1: Recent Results and Prospects for Correlation ECE ...Recent Results and Prospects for Correlation ECE Measurements on TCV L. 1Porte 1, S. Coda , T.P. Goodman 1, A. Pocehlon , V.S. Udintsev2,

Recent Results and Prospects forCorrelation ECE Measurements on TCVCorrelation ECE Measurements on TCV

L. Porte1, S. Coda1, T.P. Goodman1, A. Pocehlon1, V.S. Udintsev2, V. Vuille1, , , , ,

1Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches enEcole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches enPhysique des Plasmas, Association Euratom‐Confédération Suisse, CH‐1015

Lausanne, Switzerland

2ITER Organization, Building 519/122, CHD, Diagnostics Division Route de Vinonsur Verdon ‐ 13115 St Paul Lez Durance ‐ France

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 1/17

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OUTLINE OF THE TALK

TCV overview

● CECE capability on TCV

● summary of measurements to date

● collisionality● collisionality● shaping (triangularity) ● poloidal angle w.r.t. line of sight

radial correlation length● radial correlation length

● conclusions from recent measurements

● future plans

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 2/17

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TCV : transport as a function of form

Ip 1MA (400kA typical)

● Bt < 1.45T

● R = 0.88 m, a = 0.25 m, R/a ~ 3.5

● elongation 0.9 < < 1.85g

● triangularity - 0.7 < < 1

● negative triangularity H-mode

● single/double null

d bl t● doublet

● snowflake

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 3/17

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TCV ECRH/ECCD X2 + X3 4.5MW : Flexible system f l t l h ti d t d ifor plasma control, heating and current drive

3 gyrotrons● 3 gyrotrons● 450kW● steerable launcher (real-time)

X d b t bit il h● X-mode but can arbitrarily change● 2 sec.

● 6 gyrotrons● 6 gyrotrons● 100kW < P < 450kW ● real-time control (F Felici 09:00 Wednesday)(F. Felici 09:00 Wednesday)

powerlauncher angle( l i ti )(polarisation)pulse rate

● 2 sec.

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 4/17

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MEASUREMENTS ON TCV: motivation

= + 0.4 0.4● increasing eff decreases thermal diffusivity (e)

● factor 2 decrease in e from positive to negative triangularity

= - 0.4● is there a measurable trend in electron turbulence as function of eff or in δ ?

( )

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Electron Cyclotron Resonance Heating 5/17

Y. Camenen et al; Nucl. Fusion 47 (2007) 510–516

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MEASUREMENTS ON TCV : reduction in icross power as υeff increases

n = 1 1 x 1019m-3 ; T = 1 3keVne= 0.9 x 1019m-3 ; Te = 1.8keV

-40(H

z-1 )

ne= 1.1 x 10 m ; Te = 1.3keV -45

r den

sity

-50

ral p

ower

-55

ss s

pect

r

-60

log.

cro

s

20 40 60 80 100 120 140 1600Frequency (kHz)

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Electron Cyclotron Resonance Heating 6/17

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MEASUREMENTS ON TCV : dramtaticd ti i L ireduction in Lc as υeff increases

A.Pochelon, 52rd APS DPP, 8‐12 Nov. 2010, Chicago, NI2 6

at given power, Lc very sensitive to density, which needs to be well controlled

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 7/17

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MEASUREMENTS ON TCV: δ scanP fil t l i ECHProfile control using ECH necessary

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 8/17

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MEASUREMENTS ON TCV: large reduction in t b l i f t δturbulence on going from +ve to ‐ve δ

yow

er

Den

sit y

Cro

ss P

oS

pect

ral

Fluctuation level too lowfor good estimate of Lc in this run.

C S

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Electron Cyclotron Resonance Heating 9/17

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CECE ON TCV : the measurement of turbulence

• single,fixed, Gaussian-beam line-of-sight measurement from LFS

• 2 tunable, narrowband (170 MHz) YIG filters

• range 69-81GHz 0 0<ρ <0 7• range 69-81GHz, 0.0<ρV<0.7

• accessible k < 112 m-1 or ks < 0.3 at 500 kHz

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating

• optical thickness < 5 : care required in interpretation 10/17

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RECENT MEASUREMENTS ON TCV: poloidal angle

LORB GK i l li l b l [Cn = 2

● LORB GK simul. linear, global [Camenen, Bottino05] show spatial structure of instabilities at varying poloidal wave number

n   2

● at differing poloidal angle (plasma height) might expect to be able to measureexpect to be able to measure

either spectral differences in turbulencen 10 spectral differences in turbulence

or radial extension of modes (correlation l th)

n = 10

length)

● conduct an extensive set of measurements to examine the experimental feasibility of this idea

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating

A.Pochelon, ITC‐21, Toki, Japan, Nov. 28 2011

11/17

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RECENT MEASUREMENTS ON TCV: poloidal angle

# 43131Z = 17cm

# 43497Z = 0cmTe(keV)

vol

ne(x1019)

() 0 7 ( ) 0 7()  0.7 3fece 75.5GHz

()  0.7 3fece 71.5GHz

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Electron Cyclotron Resonance Heating

vol12/17

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RECENT MEASUREMENTS ON TCV: poloidal angleS i i t l t tSurprising spectral content

-50

-55

ctrum  ● some increase in amplitude

away from Z=0

-60

wer Spe

c # 43123● distinct changes in the spectral content

-65

Cross Po

w

● at Z= 0 lower high n content than off-axis

-75

Log C

# 43497● unexpected observation

20 60 100 140 180

-75

Frequency (kHz)

# 43497

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Electron Cyclotron Resonance Heating 13/17

Frequency (kHz)

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RECENT MEASUREMENTS ON TCV: poloidal angleL i l id l l h

Z 0 ; L (1 0 06) cm

Lc varies as poloidal angle changes

Z = 0 ;  Lc (1  0.06) cmZ = 5 ;  Lc (1.9  0.6) cmZ = 10 ; Lc (1.6  0.3) cm

( )Z = 17 ; Lc (1.7  0.9) cm

cien

t

● attempt made to estimate di l l i l h f

on coe

ffi

(15 – 120) kHz

radial correlation length of turbulence

correlatio ● can resolve differences

between plasma height

Log. of c

(15 – 60) kHz● need more data points in the scan but very time consuming with only two channels

Radial separation of resonances (cm)

with only two channels

Radial separation of resonances (cm)

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 14/17

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CONCLUSIONS FROM RECENT MEASUREMENTSd t i diff t l igood measurements in different plasma scenarios 

CECE on TCV● CECE on TCV

(i) measured factor 2 reduction in Lc by increasing eff

(ii) measured reduction in turbulent amplitude at mid-radius between +ve and –ve δ+ve and ve δ

both of these observations are consistent with global measurements of electron energy confinement

(iii) observed changes in spectral content of turbulence in moving from(iii) observed changes in spectral content of turbulence in moving from z=0 to z=17 w.r.t. plasma mid-plane : needs more work to explore and confirm these observations

(iv) measurement of Lc at different poloidal angle (plasma height)

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 15/17

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FUTURE PLANS: 4 new channels & 2 new mixerswill install 4 additional channels to have 6 channels in all1

two new mixers and front end amplifiers for the front end of the CECE● two new mixers and front end amplifiers for the front end of the CECE diagnostic1

at present signal shared between CECE and standard ECE radiometer so signal loss is an issueat present signal shared between CECE and standard ECE radiometer so signal loss is an issue

will allow measurements over a broader range of the plasma volume (HFS & LFS measurement)

1 EFDA support granted for these equipment purchases

Radial coverage for Lc measurementi h tin one shot

07/06/201217th Joint Workshop on Electron Cyclotron Emission and 

Electron Cyclotron Resonance Heating 16/17

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FUTURE PLANS: high gain antenna & th ti di tisynthetic diagnostic

● upgraded CECE radiometer to be used on a high resolution antenna that can be swept pg C C g ppoloidaly and toroidally

allow access to higher wavenumber : kθ < 174m-1 or kθs < 0.5 at 500 kHz

will facilitate the study of ‘plasma height effects’ by allowing poloidal scan to access different plasma volumes

● synthetic diagnostic being ‘constructed’ to allow good comparison between theory and experiment and should allow theory to guide experiment more efficiently : GENE local simulations (and eventually global simulations)simulations (and, eventually, global simulations)

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Electron Cyclotron Resonance Heating 17/17