21st IAEA Fusion Energy Conference- Summary Session S(tability), D(ivertor, plasma wall interaction) and W(aves and fast particles) Hartmut Zohm MPI für Plasmaphysik, EURATOM Association 21 st IAEA Fusion Energy Conference, Chengdu, China, October 21, 2006 21st IAEA Fusion Energy Conference- Summary Session
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S(tability), D(ivertor, plasma wall interaction) and W ... · Session D(ivertor, plasma wall interaction and SOL) • retention of H, D, T may be a showstopper to fusion reactors
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21st IAEA Fusion Energy Conference- Summary Session
S(tability), D(ivertor, plasma wall interaction)
and W(aves and fast particles)
Hartmut Zohm
MPI für Plasmaphysik, EURATOM Association
21st IAEA Fusion Energy Conference, Chengdu, China, October 21, 2006
21st IAEA Fusion Energy Conference- Summary Session
21st IAEA Fusion Energy Conference- Summary Session
Some statistics…
Session D(ivertor, plasma wall interaction and SOL): 39 papers
• Retention of H, D, T and gas balance: 10 papers
• Bursty SOL transport (including ELMs): 9 papers
• Alternative wall materials (W, liquid-Li) + coatings: 6 papers
• Wall material erosion, deposition, migration: 4 papers
• Divertor physics (detachment): 4 papers
• Miscellaneous: 6 papers
Session W(aves and energetic particles): 26 papers
• MHD + fast particles (AEs, NTMs) and their effect on H&CD: 10 papers
Plasma startup w/o use of central solenoidby a combinationof ECH and verticalfield ramp in LATE
Plasma startup w/o use of central solenoidby a combinationof ECH and verticalfield ramp in LATE
21st IAEA Fusion Energy Conference- Summary Session
Session S(tability)
21st IAEA Fusion Energy Conference- Summary Session
Session S: Resistive Wall Modes
(Positive) surprises as we go to lower net momentum input…
• the rotation threshold may be very sensitive to ambient error field!
• but physics not yet clear (e.g. role of νi as highlighted by NSTX)
JT-60 UJT-60 U
DIII-DDIII-D
21st IAEA Fusion Energy Conference- Summary Session
Session S: Resistive Wall Modes
Note: progress in this area also from RFPs (for which it is even more vital)
EXTRAP2-TREXTRAP2-TR RFXRFX
21st IAEA Fusion Energy Conference- Summary Session
Session S: Neoclassical Tearing Mode Control
Demonstration of individual elements as well as integrated feedback
Feedback controlledDeposition in DIII-DFeedback controlledDeposition in DIII-D
NTM stabilisation with ITER relevant broad deposition in ASDEX Upgrade
NTM stabilisation with ITER relevant broad deposition in ASDEX Upgrade
21st IAEA Fusion Energy Conference- Summary Session
Session S: Neoclassical Tearing Mode Control
But extrapolation of ITER requirement on jECCD/jbs still difficult
most optimistic prediction (La Haye et al.)most pessimistic prediction (Sauter et al.) most optimistic prediction (La Haye et al.)most pessimistic prediction (Sauter et al.)
21st IAEA Fusion Energy Conference- Summary Session
0
20
40
60
0 5 10 15 20 25
t dis-t
MH
D (
ms)
rdep
(cm)
disruption avoidance
#29979 & #29963#29984
Ip= 500 kABt= 5.3T
<ne>=0.6x10 20 m -3
LBO with Mo
Session S: Classical Tearing Mode Control
Research opportunity for any tokamak with ECRH system!
Disruption avoidance by ECCD at q=1 and q=3/2 in FTU
Disruption avoidance by ECCD at q=1 and q=3/2 in FTU
Study of magneticisland heating byECCD in TEXTOR
Study of magneticisland heating byECCD in TEXTOR
21st IAEA Fusion Energy Conference- Summary Session
Session S: Disruption characterisation and Mitigatio n
Mitigation by (noble) gas (jet) makes good progess(AUG, C-Mod, DIII-D, HL-2A)
• jet penetrates the edge only, but MHD takes over!
Nimrod modeling of C-ModNimrod modeling of C-Mod
Reduction of halo currentsby noble gas injection (C-Mod)Reduction of halo currentsby noble gas injection (C-Mod)
21st IAEA Fusion Energy Conference- Summary Session
Session S: ELM physics and control
Several routes to mitigate ELMs are pursued in the programme in
• may need several options (ITER has unique combination of ν* and n/nG)
Time (s)28 29 30 31 32
(a.u
.)M
J10
19m
-3
Dαααα
<ne>
H98 ≈≈≈≈ 0.95
Wtot
nped also constant
0
10
2.5
67911 Blue: New#66476
Red:Previous experiment #62430
Type II ELMsnow also on JET
Type II ELMsnow also on JET
Supression of ELMs byhelical field on DIII-D
Supression of ELMs byhelical field on DIII-D
21st IAEA Fusion Energy Conference- Summary SessionSummary: Progress in high priority issues
and future research directions
Retention of hydrogenic fuel: the problem is clearly defined, we needdetriation techniques and assessment of alternative wall materials.
Bursty SOL transport: good experimental characterisation, need betterlink to theoretical predictions/modeling.
Fast particle physics: field is opening up as we develop better diagnostics,need to measure better the damping rates to assess ITER situation.
CD: electron-based schemes relatively well understood, ion-basedschemes need further investigation. In particular: need to understand better effect of MHD and fluctuations on CD.
(N)TMs: control by ECCD makes rapid progress, further enlargecross-machine scalings to strengthen predictive capability.
RWMs: a positive surprise – but have to understand lower rotationthresholds before we draw conclusions for ITER.
ELMs: number of control schemes increasing, applicable at quite different plasma parameters! In lack of a non-linear ELM model, this is reassuring.