Active Beam Spectroscopy in Hot Fusion Plasmas (Introduction) Seminar-I Institute for Plasma Physics...

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FO M -Instituut vo o r PlasmafysicaA sso ciatio n EU RATO M -FO M

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Active Beam Spectroscopy in Hot Fusion Plasmas

(Introduction)

Seminar-IInstitute for Plasma Physics

Academy of SciencesHefei, ChinaMay, 5, 2007

Acknowledgement:CXRS groups at JET, TEXTOR, Tore Supra , ASDEX-UG andmembers of the ITPA expert group on Active Beam Spectroscopy

Manfred von HellermannFOM Institute for Plasma Physics Rijnhuizen, NL



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1) Introduction to Active Beam Spectroscopy

2) Spectral Analysis, Evaluation and Simulation Codes

3) Beam Emission Spectroscopy and MSE



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Outline

Basic concepts of active beam spectroscopy (CXRS + BES)

CXRS on JET

Global Consistency Checks based on CXRS

CXRS and BES on ITER making use of a DNB



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CXRS Aims :1) Helium ash measurement2) Impurity ion densities3) Fuel mixture and density4) Plasma rotation5) Ion temperature6) Particle transport studies

BES & MSE Aims :1) Localisation of active volume2) Local Beam Density (BES)3) Density Fluctuations(BES)4) Local pitch angle (MSE)5) Local Lorentz field (MSE)



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Active Beam Spectroscopy ( basic principles)

localized measurement

quantitative use of intensities

intrinsic consistency of temperature, rotation

and density

advanced collisional radiative atomic

modelling

beam emission spectroscopy as

indispensable collateral to CXRS

BES and MSE



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Courtesy: Carine Giroud



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dsEnZTnEQnEI beffieBESebes )(),,,(4

1)(

Beam Emission Spectroscopy on TEXTOR

D-CXRS



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Combination of CXRS and BES:

common line of sight and beam geometry

Beam Emission Spectroscopy as tool for absolute calibrationof CXRS signals

eEDeED )()( *

)()()()( ,*02 EDTHeEDTHe



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local concentration measurements reduced to a line ratio measurement

ds)E(nQn4

1)E(I bBESebes

Combination of CXRSand BES enablesdeduction of ion densities without absolute calibrationand measurement of optical transmission

Combination of CXRSand BES enablesdeduction of ion densities without absolute calibrationand measurement of optical transmission

ds)E(nQn4

1)E(I bCXRSzCXRS

CXBES

BESCX

e

z

QI

QI

n

n

Note: Atomic rates Q depend on energy, electron and ion densities and temperatures



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Ion Temperature, Velocity and Density measurement

• Ion Temperarure deduced from Doppler width.

• Velocity can be deduced from Doppler shift

• Density can be deduced from measured intensity

• <Zeff> can be deduced from

continuum background

Ti

v

Reference line

For global consistency all physics parameters extracted simultaneouslyfrom CX spectrum including its baseline need to be validated



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Variation of the cross-section with beam energy

D0+He2+ -> D+ + He+ (n=4 -> n=3)

D0+Be4+ -> D+ + Be3+

(n=6 -> n=5)

D0+C6+ -> D+ + C5+ (n=8 -> n=7)

Intensity of Charge-exchange emission

Effective CX emissionRates provided by ADAShttp://adas.phys.strath.ac.uk

http://adas.phys.strath.ac.uk/

Core CXRS diagnostic at JET

• Spatial resolution: limited by l.o.s. intersection of flux surfaces in beam volume

•Time resolution: limited by detector readout ~50ms.




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Parasitic emission to active charge-exchange emission

• Parasitic emission:

electron impact and passive CX emission of other species coming from the edge of the plasma.

C2+ electron impact

Be1+ electron impact

C5+ charge-exchange spectra



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• Parasitic emission:

passive charge-exchange with thermal deuterium neutrals

Parasitic emission to active charge-exchange emission

Line of sight

Neutral beam

Zone of high passive charge-exchange

C5+ active CX

C5+ passive CX

Top view of torus



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Some JET CXRS results



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Example of the use of Charge Exchange measurements

Internal transport barrier #51976




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Example of the use of Charge Exchange measurements

• Impurity transport studies

Crucial to study impurity behaviour

Low and high Z impurity: fuel dilution (He ash)

High Z : radiative collapse




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CHEAP

Charge Exchange Analysis Package

Mapping of physics quantities on symmetrised

coordinates (magnetic flux surface indices)

Monitoring of main low-Z ions including bulk ions

Self consistent calculation of beam-target interaction

processes

Primary data consistency checks

(effective ion charge, kinetic plasma energy,

neutron yield



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Zeff contributions from C+6, Ar+16 and Ar+18

JET pulse#61388



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Zeff-Visible Bremsstrahlung (Abel inverted)

Zeff reconstructed from C+6, Ar+16 and Ar+18



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Reconstruction of Thermal and Beam -Thermal Neutron yield in DT plasma



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Chris Walker, ITER CT

Diagnostic beam for ITER: E=100keV/amu, P=3.6MW, div=10mrad, distance to blanket opening 19.2m

M. von Hellermann



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Table II200 keV, 50 A D beamSource Dimensions : Y = 1.53 m (high) and X =0.58 m Divergence of the main beam : 10 mrad

8.58.258.7

1.71.651.74

666

0.2830.2750.29

303030

303030

101010

101010

0.1080.1080.108

0.1080.1080.108

19.2

19.2

19.2

19.2

21.5

19.2

21.519.219.2

IIIIII

’(mrad)

’(mrad)

(mrad)

(mrad)

Y’(m)

X’(m)

Current (A)

Power at observation point

(MW)

Launched power

(MW)

Fractional power transmit

ted

Halo component(15% main

beam

Divergence

(85% main beam)

Aperture dimensio

ns

Apertur

e locatio

n (m)

Fy(m)

Fx(m)

Case

Courtesy: Drs M.Singh, S.Mattoo, Institute for Plasma Research, India



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Conceptual optics designfor ITER Core-CXRS U-portperiscope combining neutronlabyrinth and Cassegrain outputoptics

full view of DNB path (2m)

(double) vacuum window

cassegrain optics

rear part of port plug

fibers to spectrometer

adjustment mechanism

Double Vacuum Window

Adjustment mechanism

Rear of periscope

Fibres to spectrometers

Cassegrain output to fibres



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Optics layer

Step 4•Placing of upper shielding blocks•Connection blocks to cooling system

Shielding block

Shielding block

TNO periscope design:“Central Removable Tube” containing First-Mirror and ShutterFriso Klinkhamer, TNO



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Proposed active

(focussed on DNB) and passive

(off-beam)

fibre bundles



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TRINITI Spectrometer

ITER CXRS proto-type spectrometer developed by TRINITI, Troitsk, RF

Echelle 15th order, F/3, f=500mm, 0.25nm/mm



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Littrow spectro + Pixelvision ccd

TRINITI spectro + Pixis 400B ccd

# 104461CVI @ 5290Asame line of sight

Red: during NBIBlue: before NBI



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Parameter Range Time Res Space res accuracy

Vtor 1-200 km/s 10 ms a/30 30%

Vpol 1-50 km/s 10 ms a/30 30%

Ti, core (r/a<0.9)

0.5-40 keV 100 ms a/10 10%

Ti, edge (r/a>0.9)

50eV-10 keV

100 ms Tbd 10%

Core He density

1-10% 100 ms a/10 10%

ITER CXRS measurement requirement table



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rTz

wDerfwrerf

BLgZe

cdrncI

N

S

obsde

perpblanketperp

pffeff

zstopzzeCXn

2/

)/()/(

sin8

}exp{

)(

2

2

,

2/1



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Simulated Continuum level, fluctuation and HeII signal strength for ITER U-port 2 (left) and U-port-3 (right)

U-port-3 continuum level is slightly below U-port-2 level due to shorter path length through plasma

Error Analysis for CVI, U-port-2, =100ms

Error Analysis for simulated HeII spectra, ITER Upper-port-2, =100ms,Doppler width and shift deduced from simultaneously analysed CVI

D-alpha-edge

D-alpha-CX

DNB induced MSE and CXRS spectrum , B=5.3T, E=100keV/amu



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MSE and CXRS on D error analysis



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Summary remarks

Active Beam Spectroscopy offers a rich diagnostic potential

for present and future fusion experiments

Substantial progress has been achieved in a quantitative

analysis of active spectra and results are considered as

indispensable input for plasma interpretation codes

Advanced atomic modelling and self consistent analysis

procedures have led to a general acceptance of CXRS as a

reliable diagnostic and plasma control tool

Future fusion devices as ITER do envisage the use of CXRS

with challenging demands on components and beam sources

Active Beam Spectroscopy in Hot Fusion Plasmas (Introduction) Seminar-I Institute for Plasma Physics...

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