Untitled-3 [conferences.iaea.org]...0.1 0.2 0.3 target x-point Spatial profiles (n e / n GW ~ 0.48)...
Transcript of Untitled-3 [conferences.iaea.org]...0.1 0.2 0.3 target x-point Spatial profiles (n e / n GW ~ 0.48)...
5 Nov. 2019, IAEA Headquarters, Vienna, Austria
Atomic Daestimate Da [atom]
F (n)
ETe
RTeBn->2rec
Bn->2exc
Measured Da
ne
Bn->2
Da [D2,D2+,D-]
- ETe
Da [D2]
Da [D2+, D-]
EstimateDamax D2
ne
nD₂/neΔL
RTe
Db [D2+, D-]
SeparateDa [D2+, D-]
neRTe
TD₂
EstimateDamax D2
ne
nD₂/neΔL
RTe
Spectroscopic analysis
Previously, atomic particle/powersources & sinks measured [1,2]
Particle balance
Power balance
Dα measurements
TCV density ramp: 3 phases
1) Attached & I (ion current)t I (ion source)i
rise linearly with ne
>> Precl Pion
2) Detachment start flattens -> deviates from Ii It
linear increase with ne
~ 2 Precl Pion
3) roll-overIt
rolls overI (ion source)i
lesser roleI (recombination)r ~ Precl Pion
At detachment onset, Dα rises above estimationsatomic
+D
D-
D
D2+
D2
+D3
Dα
Mol. Dα too low, but in+(D , D) SOLPS2
agreement after post-processing
• -> reactions with Mol. Dα + -D D2
• Underestimated by SOLPS-> Radiation (power losses)-> Particle gains/losses (MAR/MAI) ‘Post-processed’ SOLPS: AMJUEL (vibr. states)
Preliminary results
9
Investigating the in�uence of molecules on power/particle/momentum balancein the detached TCV divertor
Dα > expected (atomic)
Conclusions
Measurement details (spectroscopy)
Third IAEA Technical Meeting on Divertor Concepts
a b,aa,b b c b a c d,a a c K. Verhaegh , B. Lipschultz , B.P. Duval , B. Dudson , A. Fil , O. Février , D.S. Gahle , J.R. Harrison , L. Martinelli , D. Moulton , O. Myatra , e c c * **A. Perek , C. Theiler , M. Wensing and the TCV and EUROfusion MST1 teams
PII 37
Measured Estimated (atomic)
SOLPS (syn. diag) Total (AMJUEL Atomic
Molecular (AMJUEL Molecular (SOLPS)
0
1
2
0.2 0.3 0.4 0.5
D
α (
10
21 p
h/s
)
Core Greenwald fraction
0
5
10
15
0
0
50
100
150
200
10
21 io
ns/
s
It
Ii
Ir
Pow
er (k
W)
Precl
Pion
Pdiv
vibr. states)
vibr. states) • Increased (mostly ) hydrogenic radiation +D2
• Increased ion losses ( ) (due to & ) - MAR +D2
-D
larger than ( )electron-ion recombination EIR
- - ( + ) < Ionisation MAR EIR ion target �ux
• Onset of near ‘power limitation’+D MAR2
/detachment, followed by andD MAR EIR
• Increase ion source ( & D₂) negligibleMAI +D2
0.4 0.5
Cause? ? Moleculesreaction -> excited atom -> emission
0
10
15
4
7
10
30
0.2 0.3 0.4 0.5
Core Greenwald fraction
+D
D-
D
D2+D2
+D3
Dα
Position wrt target (m)0.1 0.30.2
target x-point
Spatial profiles (n / n ~ 0.48)e GW
Density ramp
Particle balance2110 ions/s
Particle losses21
10 ions/s
Ion target currentIonisationRecombination
+MAR H2
MAR -H
Hydrogenic radiation(kW)
1
2
Fulcher (600-616 nm) 4
emission (x 2 10 )Break-down of Dα
21 2(10 ph/s m )
0
0
0
Ion sinks /sources21 2(10 part. / m s)
33
66
4
8
12
5
0
0
#56567
#56567
Preliminary conclusion / DEMO implications :
• Signi�cant contributions-> Balmer lines
• (eg ) near cold target ->Mol. Dα +D2
- Dassociated MAR/rad. loss near target;+D2 ,
- D
below ; wider than ion. region EIR region
• [5] atFulcher (600-616 nm) emission different location than ion Dα emiss
+D2 - D
No extra Dα with N seeding2
assuming
• Dα emission & anti-correlation Dα & I cannot be explained with atoms t+ - • Additional Dα could be due to D (and/or D ) - only high with CX & vibr. states2
• Additional Dα does not appear during N seeding 2
• Particle/power losses plasma-mol. interactions have been analysed experimentally
[3]
[1]: K. Verhaegh, et al. NF, 2019[2]: K. Verhaegh, et al. PPCF, 2019[3]: K. Verhaegh, Thesis, 2019[4]: D. Wünderlich, U. Fantz; Atoms; 2016[5]: U. Fantz, et al. 2001, JNM[6]: M. Groth, et al. 2019, NME
a Culham Centre for Fusion Energy, Culham, UKb York Plasma Institute, University of York, UK
c Swiss Plasma Center, EPFL, Lausanne, Switzerlandd University of Strathclyde, Glasgow, UK
e DIFFER, Eindhoven, The Netherlands* See author list of ‘B. Labit, et al 2019, Nucl. Fusion 59 086020'** See author list of ‘S. Coda, et al 2019, Nucl. Fusion accepted'
Detachment introduction
• Detachment: Simultaneous reduction , T t It
Requires:• Particle losses (ion sink/power limitation• Power losses• Momentum losses
Analysis: Balmer n=5,6 atomic only
rec
RTe
Existing atomic particle/power sink source analysis [2]
Recombination rate
Ionisation rateIonisation rateIonisation rateIonisation rateIonisation rate
+Da [D ]2
Balmerline shape
(n>6)
Stark broadening
ne
Balmerline ratio
Frec(n)
Frec(n)
Bn->2
Bn->2exc
Bn->2rec
Recombination rate
ne ΔL
neno/ne
IL
Prad,Lexc
RL
ΔL n/no e
Prad,Lrec
Fexc(n)
Analysis steps InputOutput
ETe
Molecular particle/power sink source analysis; with Yacora [4]
MAI per Dα+[D₂ D₂ ] (AMJUEL)
Rad. per Dα+ [D₂ D₂ D ] (YACORA)
Atomic Dαestimate Dα [atom]
ETe
RTeBn->2rec
Bn->2exc
Measured Dα
ne
Bn->2
- ETe
[D2]
+ -Dα [D₂ D₂ D ] Dα [D₂] SOLPS estim
Dα [D₂]
+ -Dα [D₂ D ]
Separate(with Dα/Dβ)
+ -Dβ [D₂ D ]
+Dα [D₂ ]-Dα [D ]
MAR per Dα+ [D₂ D ] (AMJUEL) MAI
MAR
Rad. power
Obtain : molecular Dαmolecular = -total atomic
Separate mol. Dαin parts+ D₂ D₂ D
Dα ( ) X + D₂ D₂ D rad./reac per Dα photon ratios
Molecular = -Total AtomicAssume all ‘missing’ Dα -> plasma-molecule
Veri�ed against syn. diagnostic (SOLPS)
Estimation mol. contributions other Balmer lines
Iterative scheme
Balmer n=3,4,5,6 - atomic & molecular
Density ramp
• Signi�cant contributions ocation emission D different to 2+
D2
- D
emission, & regionradiation MAR
Lyβ(~40%)
Lyα (~40%)
Emission /absorption
[SOLPS simulations MAST-U post-processed]
-> Different location , Lyβ Lyαemission -> opacity of both signi�cant
Total
15
Contribution plasma-mol.Balmer lines (%)
n=3n=4n=5n=6
• Power losses: signi�cant plasma-mol. rad in hydrogen spectra during detachment (similar to atomic excitation radiation); losses mol. bands small [6]; • Particle losses/gains: signi�cant MAR larger than EIR• Plasma-mol. interaction can in�uence Balmer & Lyman series lines
• The inclusion of those losses in plasma-modeling codes may be limited-> important for extrapolating to DEMO
Plasma-mol.-> implications for opacity