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TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Influence of the Dynamic Ergodic Divertor (DED) on ELM activities
and on confinement
K.H. Finken1, S. Abdullaev1, J. Coenen1, A. M. Jakubowski1, R. J. E. Jaspers2, A. Krämer-Flecken1, M. Lehnen1, Y. Liang1, B. Unterberg1, M. von Hellermann2, Y. Xu3, R. C. Wolf1, U. Samm1, O. Schmitz1, and the TEXTOR Team
1) Institut für Plasmaphysik, Forschungszentrum Jülich, Association EURATOM/FZJ, Trilateral Euregio Cluster, D-52425 Jülich, Germany, www.fz-juelich.de2) FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands, www.rijnh.nl3) Laboratoire de Physique des Plasmas - Laboratorium voor Plasmafysica, Association 'Euratom- Belgian state', Ecole Royale Militaire - Koninklijke Militaire School, B-1000 Brussels, Belgium*
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
#94809
LFS HFS DED topics:
Helical divertor
Field line and plasma topology
Impurity shielding
Field line penetration
Tearing modes
Suppression of tearing modes
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Outline:
• Introduction to DED
• Effect of the perturbation field on ELMs
• Improved confinement by DED
• Summary
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
m = 6, n = 2
m = 12, n = 4
m = 3, n = 1
Base modes for DED operation
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
H-mode characterization and ELM suppression by DED-field
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
2 2.2 2.4 2.6 2.8 30
1
2
3x 10
19
ne /
m- 3
2 2.2 2.4 2.6 2.8 30
5
10
15TEXTOR # 97315
I DE
D /
kA
2 2.2 2.4 2.6 2.8 30
1
2
3x 10
6
W
1.8 2 2.2 2.4 2.6 2.8 30
5x 10
4
ED
ia /
J
time / s
Ptot
Prad
Basic scenario: Ip= 240 kA/ Bt= 1.2 T-1.4 T, plasma shifted to HFS (R=1.68m / a=0.4m)
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
~ 500 Hz
ALTH - drop
DED
0 0.5 1 1.5 2 2.5 30
5
10
15
H /
a.u
.TEXTOR # 97315
2.5 2.505 2.51 2.515 2.520
5
10
time / s
H /
a.u
.
Characterization of H-mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
1 1.2 1.4 1.6 1.8 20
500
1000
1500
N
EL
M /
Hz
ELM frequencies TEXTOR limiter H-mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Power threshold about twice the L-H threshold in divertor tokamaks – “typical” for limiter H-modes
4 5 6 7 8 9 10x 10
5
0.8
1
1.2
1.4
1.6
1.8
2
P sep /
W x
10
6
PL-H thresh, IAEA96 / W
o no DED
+ with DED
# 97300/1, 97312/14/15, # 98296, 98491, 99595
with ELM signature w./o. ELM signature
"dithering"
continued ELM - signature over 1s
# 97314
# 98491 (L-H transition)
Predictive RITM code calculations for 1.3 MW heating power and
H/ (H+D) = 40%
and TEXTOR data
D. Kalupin,
M. Tokar
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Evolution of edge pressure HFSTEXTOR # 97315 (thermal He beam*)
R= 1.3 m
L-H –transition
H- L –transitionwith DED
*extension of CR model by courtesy of M. Brix
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Substantial spin up of poloidal rotation
in electron diamagnetic drift direction (indicating more negative Er)
Pnbi=2.8 MW
~18 km/s~3.6 km/s
Reflectometry
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
2.2 2.4 2.6 2.8 30
1
2TEXTOR # 97315
D /
a.u
.
2.2 2.4 2.6 2.8 30
5
10
15
I DE
D /
kA
2.2 2.4 2.6 2.8 3-1000
0
1000
v /
m/s
(C
III)
time / s
L-H transition DED induced back transition
ELM mitigation in 12/4 base mode
ELM suppression starts at 3 kA
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
ELM mitigation in 12/4 base modeTEXTOR # 97315
2.8 2.85 2.9 2.95 3 3.050
10
20
2.8 2.85 2.9 2.95 3 3.050
5
10
15
2.8 2.85 2.9 2.95 3 3.050
1
2x 10
19
t / s
D / a.u.
IDED
/ kA
nel / pedestal top
H-mode Mitigation mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
ELM mitigation in 12/4 base mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6-1
0123
TEXTOR # 98296 (Ip = 250 kA / BT = 1.4 T, R= 1.72 m, a= 0.44 m)
2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.60
2
4x 10
6
Pto
t / W
2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.60
5
D /
a.u
.
2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.60
1
2
time / s
Te /
a.u
. (
~0.
9)
ne / 1019 m-3
IDED
/ kA (AC 1 kHz)
ELM mitigation in AC 3/1 base mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Improvement of energy confinement during H-mode modest some reduction of energy confinement with DED
0.015 0.02 0.0250.015
0.016
0.017
0.018
0.019
0.02
0.021
0.022
0.023
0.024
0.025E / s
E, ITERH89P / s
w./o. ELM signature with ELM signature
o no DED
+ with DED
H89=1
H89= 1.25
TEXTOR # 97300/1, 97312/14/15
R= 1.68m
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Confinement improvement with DED in
m/n = 6/2 base mode
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Best conditions have been observed for
• strongly inward shifted plasmas
• low density plasmas, low collisionality
• Co-NBI heating
• Ip = 310 kA; Bt = 1.9 T
• IDED = 7.5 kA
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Stepwise density increase during DED-ramps
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Density profile Density time trace
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
temperature time trace pressure time trace
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
time [ms]
-
polo
idal
ang
le [
deg]
#100972, evolution of heat flux density at toroidal angle - = 208°
1600 1800 2000 2200 2400 2600 2800 3000150
160
170
180
190
200
210
0
2
4
6
8
10
12x 10
5#100972, evolution of heat flux density at toroidal angle - = 208°
time [ms]
- po
loid
al a
ngle
[de
g]
1600 1800 2000 2200 2400 2600 2800 3000150
160
170
180
190
200
210
0
1
2
3
4
5
Related to the stepwise increase of density are characteristic heat deposition patterns
Start of a new pattern is interpreted as opening of magnetic flux tubes from new island chain to wall
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
3.75kA 4/2
9/4
5/2
FP = +80V
FP = +120V
6/2
Electric potential at divertor target probes
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Poincaré plots at first and third density step
Before step After step
1. step
3. step
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Hypothesis for confinement improvement:
Important are the open magnetic field lines connecting inner islands with the wall.
The improved confinement may be related to potential exchange between wall and inner islands
This is effective only in low collisional plasmas
TEC
Trilateral Euregio ClusterInstitut für Plasmaphysik Assoziation EURATOM-Forschungszentrum Jülich
IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas, Krakow
Summary
Confinement improvements have been observed for some plasma / DED conditions.
Best conditions were found for strongly heated low density plasmas shifted strongly towards the HFS (DED).
Improvement has a resonance character with respect to q(a) and the DED-current.
On TEXTOR, a limiter H-mode has been obtained.
The ELMs were reduced at moderate ergodization levels.
12/4 and AC 3/1 base modes have been applied successfully.
The energy confinement is slightly reduced by DED.