ASDEX Upgrade Max-Planck-Institut f .. ur Plasmaphysik Active in-vessel saddle coils at ASDEX Upgrade for MHD control Wolfgang Suttrop O Gruber, D Hahn, A Herrmann, M Rott, U Seidel, B Streibl, T Vierle, D Yadikin, and the ASDEX Upgrade Team Max-Planck-Institut f ¨ ur Plasmaphysik, Assoziation IPP-EURATOM, D-85748 Garching, Germany International Collaboration: B Unterberg, O Neubauer —- TEXTOR (FZ J¨ ulich) P Brunsell —- EXTRAP-T2 (KTH Stockholm) E Gaio, V Toigo —- RFX (Consorzio RFX Padova) ITPA Pedestal & Edge Topical Group, San Diego 30 April 2008
15
Embed
Max-Planck-Institut fur Plasmaphysik fur Plasmaphysik.. Active in-vessel saddle coils at ASDEX Upgrade for MHD control Wolfgang Suttrop O Gruber, D Hahn, A Herrmann, ...
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
ASDEX Upgrade
Max-Planck-Institutf
..ur Plasmaphysik
Active in-vessel saddle coils at ASDEX Upgradefor MHD control
Wolfgang SuttropO Gruber, D Hahn, A Herrmann, M Rott, U Seidel, B Streibl, T Vierle, D Yadikin, and
⇒ Rotating error field withf ≥ 1 kHz can avoiddisruption and give controlsystem time to react
0.0
0.5
1.0
1.5
2.0
MA
, a.u
.
3.6 3.7 3.8 3.9
time [s]
0
a.u.
m=2, n=1 m=3 n=2Bθ
4.0 4.1 4.2
D α
Ip
3/2
2/11 kHz
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 7
With conducting wall: RWM stabilisation
Vacuum vessel far from plasma onlow field side
Passive stabilising loop (PSL)reduces vertical growth rate (n = 0)(opposite current direction in upper and
lower branches → radial field)
Extend with conducting wall elementsbetween PSL branches→ allow helical currents
Holes for diagnostics and heating:3D structure
Electromagnetic surface model
˜ 9000 nodes, ˜ 19000 elements
ICRH
ICRH
ICRHICRH
upper PSL
lower PSL
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 8
Physics requirements
Reference point: 10 cm in front of coil (≈ plasma boundary)
Ergodisation by resonant magnetic perturbation: σ = 3 for Bn = 0.6 mTAllow for factor 10 to accommodate shielding by plasma rotation.
RWM control requires bandwidth (thumb rule: f3dB ≥ 40× γ) and phase margin.Field amplitude depends on noise level - RWM signal must exceed background.
Mode rotation ( fmax = 3 kHz) will be done by midplane (A-) coils
Physics parametersQuantity Symbol Value Units Conditions
DC normal field min. Bn 6 mT f = 0, n = 2,3,4AC normal field min. Bn 1 mT f = 500 HzPhase lag of field max. ΦBn−V 0 . . . -150 degrees
→ Verify coil performance in presence of passive conductors (coil housing, PSL)
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 9
Technical requirements
Operational limits (individual coil)Quantity Symbol Value Units Conditions
Number of turns 5Peak coil voltage max. Vcoil 500 V f = 1 kHzDC coil current max. Icoil,DC 1 kA f = 0Operation pulse duration min. tpulse 6 sCool down time max. tpause 15 min.
Isolation voltage min. Vi 3 kV 100% testedHousing temperature max. Th,max 180 0C Icoil = 0Housing temperature max. Th,max 90 0C Icoil 6= 0
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 10
B-coil design - similar to proven W7-X control coils
• 5 turns, copper with cooling channel
• glass fabric wound around coils
• isolation: epoxy cast
• vacuum tight enclosure:1.2 mm Inconel sheet with stiffening ribs
Bu coilupperPSL
A-coil
Conductingwallcontour
Bl-coillowerPSL
outer divertor module
torusaxis
midplane
Mounted on upper and lower PSL
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 11
Electromagnetic model verifies AC capability of coils
“B”-coils : close to PSL, metal casing→ shielding by eddy currents
|Bn| at 10 cm distance to coil (QuickField)
PSL
B-coil
normaldirection
Bn,peak at Icoil,peak = 1 kA
1
10
1 10 100 1000 10000
frequency [Hz]
mag
netic
indu
ctio
n [m
T]
Bu-coilsd=10 mm
Bl-coilsd=30 mm
Phase Bn wrt. Icoil
-45
0
phas
eΦ
Bn-
I[d
egre
es]
1 10 100 1000 10000frequency [Hz]
Bu-coilsd=10 mm
Bl-coilsd=30 mm
W Suttrop et al In-vessel saddle coils at ASDEX Upgrade for MHD control 12
Time schedule
Stage Hardware component Experiments Installation
1 4 upper + 4 lower coils ELM control , n = 2 2009+ 4 upper + 4 lower coils n = 4 2010
2 + 8 midplane coils Four n = 4 2011configurations
3 12 AC power supplies Mode rotation 2012(odd or even n) n = 3 ELM control