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![Page 1: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/1.jpg)
H-mode characterization for dominant ECR heating and comparison to dominant
NBI or ICR heating
F. Sommer
PhD thesis advisor: Dr. Jörg Stober
Academic advisor: Prof. Dr. Hartmut Zohm
Advanced Course of EU PhD Network
29 Sep 2010
Max-Planck-Institut für Plasmaphysik
Boltzmannstr. 2, 85748 Garching, Germany
![Page 2: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/2.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 2
Outline
• NBI and ECR heating systems• Heat transport theory• H-mode heat transport characterization
– Te, Ti, profiles
• Further investigations and experiments• Summary and discussion
![Page 3: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/3.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 3
NBI – general introduction
• Beam of neutrals (H0, D0, T0, He0 ) injected into plasma with
– high power – up to 2.5 MW
– high (appropriate) energy – Ebeam > Ti,e
– Inside plasma neutrals collide with plasma ions & electrons
• H0 + H+ → H+ + H0 – CX
• H0 + H+ → H+ + H+ + e – Ionisation by ions
• H0 + e → H+ + 2 e – Ionisation by electrons
– exponential decay
Ebeam ~ 100 keV today
1 MeV for ITER
• Resulting fast ions are confined within the plasma by magnetic field
slowed down to thermal energies Coulomb collisions ions & electrons
transfer of beam power to plasma
mnA
E AUGD
e
5.018
![Page 4: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/4.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 4
• critical energy: rate of energy loss to ions = rate of energy loss to electrons
• Ecr = 14.8 (kTe) [ (A3/2/Ai) ]2/3
– for pure D – beam: Ecr = 19 Te Ebeam/Ecr ~ 1 – 3
ITER: ENBI = 1MeV
E = 3,5 MeV
NBI – power deposition
![Page 5: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/5.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 5
NBI – layout
ASDEX Upgrade
neutraliser
ion dump
magnet
PINIs (4x)
box height:~ 4.5 m
cut through 1st injector – 10 MW at 60 kV
– arc sources pins have to be replaced quite often
– 10 MW at 93 kV– RF sources
simpler, cheaper, less maintenance
- pulse = 10 s
![Page 6: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/6.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 6
NBI – layout
• 2 Beamlines, each 4 ion sources
• SO-injector
• 2 radial beams
• 2 tangential beams
• NW-injector
• 2 tangential beams
• 2 off-axis deposition
• Also source of :
• particles edge: 1/10, but deep fuelling (not relevant for ITER)
• driven current
• plasma rotation (by NBI torque)
• CXRS
• efficiency factor of only 40 %
![Page 7: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/7.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 7
ECRH – principle
• Electron Cyclotron Maser Instability
• Electron gun: hollow e- beam
• Accelerated to relativistic speeds and focussed
• vII converted to v┴ inside resonant cavity (axial B-field)
• Interaction between e- and em wave
• Phase focus of e-
• Slowing down of e- by E transfer to
HF field
• Vgyrotron = 73 kV
Bgyrotron = 5.3 T
• Efficiency factor of 50 %
![Page 8: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/8.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 8
ECRH – layout
• fECRH ~ 140 GHz
• Electron cyclotron frequency fce(B = 2.5 T)= eB / (2me) = 70 GHz
• location determined by
– B 1/R
– fECR
– launching angle (mirror)
• Pold = 4 x 0.5MW for 2 s
• Pnew = 2 x 1 MW for 10 s
• Pfuture = 2 x 1 MW for 10 s
![Page 9: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/9.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 9
ECRH – advantages
• Localized (few cm) deposition
• Localized current drive
removal of NTMs by heating inside island structure
• Electron heating simulate reactor conditions
• Fast modulation ( 500 Hz) fast response in plasma
• Central heating enhanced impurity transport
![Page 10: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/10.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 10
Heat transport - theory
• Why are we interested in heat transport?
– High E low heat transport
– High central density low particle transport
– Low accumulation of impurities enhancement of impurity transport
• Heat transport is not governed by classical or neoclassical drive, but by micro instabilities and turbulent effects
– ITG, TEM, (ETG)
– Scale length ~ ion gyro radius << a
• qe(r) = - ne(r) · e(r) · Te(r)
• (r) = - D (r) · ne(r) + v · ne(r)
![Page 11: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/11.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 11
Heat transport - theory
• Gyro-Bohm scaling law in H-mode.
• Turbulence increases above a critical gradient length:
•
• S, 0, R/LTe, crit adjusted to experiment
stiffness of profiles
• Boundary condition at pol = 0.8 (H-mode pedestal)
GBTT
GBsPBe F
L
R
L
RFq
critee
02/3
,
e
e
T T
TR
L
R
e
2/3,e
iLeGB T
ReB
TF
![Page 12: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/12.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 12
ASTRA
• Automated System for TRansport Analysis in a tokamak
• 2D equilibrium
• 1D (radial) profiles and transport equations
• of transport
• Modular build
– Many implemented models
– Easy inclusion of own models
• Equilibrium + radial profiles (Te, Ti, ne, j, Pheat,, Prad, …) qe,i, e,i, Dn, …
• Equilibrium + radial profiles (ne, j, Pheat ,, Prad, …) + i,e,theory radial profiles (Te, Ti)
DGL
![Page 13: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/13.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 13
H-mode characterization
• 4 similar discharges: Ip ~ 600 kA, Btor ~ 2.5 T, ne ~ 5 x 1019, PNBI = 5 MW
– Different heating power (PECRH = 0, 0.5, 1.5 MW)
– Different deposition location: PECRH = 1 MW, pol = 0, 0.3, 0.6
![Page 14: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/14.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 14
• Power dependence of Te profiles with varying ECRH:
• 0.6 kA, 2.5 T, central ECRH
• ne = 5x1019
H-mode characterization - T profiles
![Page 15: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/15.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 15
• Power dependence of Te profiles with varying ECRH deposition location:
• 0.6 kA, 2.5 T, PECRH = 1.2 MW
• ne = 5x1019
H-mode characterization - T profiles II
R.M.McDermott et al 2010 EPS
![Page 16: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/16.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 16
H-mode characterization - e profiles
• Electron and ion heat diffusion coefficients derived with ASTRA
with varying heating power
Transport dominated by ion heat transport (ITG)
![Page 17: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/17.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 17
• Increase of ECRH power (6 MW) Replacement of NBI in H-mode
• Higher current values up to Ip ~ 1.2 MA
• Lower density values ne < 5x1019
Increased influence of ECRH on e (TEM) due to decreased *
• Variation of R/LTe by variation of ECRH
• Dependence of ei on energy confinement time E
• Influence of central ECRH on pedestal
Further experiments and investigations
![Page 18: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/18.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 18
H-mode characterization – ECRH on edge
• Influence of ECRH power on edge profiles (Te, vtor, ne)
Analysis by Elisabeth Wolfrum
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Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 19
• Increase of ECRH power (6 MW) Replacement of NBI in H-mode
• Higher current values up to Ip ~ 1.2 MA
• Lower density values ne < 5x1019
Increased influence of ECRH on e (TEM) due to decreased *
• Variation of R/LTe by variation of ECRH
• Dependence of ei on energy confinement time E
• Influence of ECRH on pedestal
• Analysis of ICRH heated plasmas: torque e-/D+ heating
Further experiments and investigations
![Page 20: H-mode characterization for dominant ECR heating and comparison to dominant NBI or ICR heating F. Sommer PhD thesis advisor: Dr. Jörg Stober Academic advisor:](https://reader035.fdocuments.in/reader035/viewer/2022081518/55159f4855034674578b5eab/html5/thumbnails/20.jpg)
Advanced Course of EU PhD Network, 29 Sep 2010F. Sommer 20
• Difference between NBI and ECR heating
its influence on transport
• Gyro-Bohm scaling law
• Examples of ECRH influence on heat transport
• Increase of available ECRH power increases the range of accessible parameter space to analyse heat transport.
Thank You
Summary and discussion