Embed Size (px)
DESCRIPTION
HHFW Current Drive, RF-Only H-modes, and HHFW+NBI. presented by Phil Ryan (ORNL) for J. Hosea, B. Leblanc, R. Pinsker, D. Swain, J. R. Wilson, and the NSTX HHFW Team. NSTX Results Review Sept 20, 2004. HHFW Operation in 2004. Developed DND HHFW plasma scenarios - PowerPoint PPT Presentation
Citation preview
HHFW Current Drive, RF-Only H-modes, and HHFW+NBI
presented by Phil Ryan (ORNL)for J. Hosea, B. Leblanc, R. Pinsker, D.
Swain, J. R. Wilson, and the NSTX HHFW Team
NSTX Results ReviewSept 20, 2004
HHFW Operation in 2004
• Developed DND HHFW plasma scenarios–Separate plasma fueling from antenna coupling
–Center stack gas injector and DND geometry
• Operated with rtEFIT control of plasma position.
• Installed Langmuir probes at antenna array.
• Extended HHFW CD to higher density, DND plasmas (XP403).
• HHFW Driven H-mode plasma operational envelope expanded (XP425 - Leblanc)
• Combined HHFW-NBI operation (XP413 - Leblanc)
• ERD measurements show ion heating in peripheral region
HHFW CD at kz = 7.6 m-1
HHFW on
1.50
1.25
1.00
0.75
0.50
0.25
0.00
Loop Voltage (V)
0.60.50.40.30.20.10.0
time (s)
cntr-CD
co-CD
8x104
6
4
2
0
Stored Energy (J)
0.60.50.40.30.20.10.0
time (s)
4
3
2
1
0
RF Power (MW)
Stored Energy and RF Power Loop Voltage (corrected for dI/dt)
• Operation at 30% higher density gave ICD ~ 100 kA for P = 4.2 MW (2.7 MW co-CD, 1.5 MW cntr-CD). Te(0) = 1.7 keV, ne(0) = 2.1x1019 m-3, He, double-null diverted, Ip = 0.5 MA, 0.45
T.
Ryan NSTX Results 2004
CURRAY
AORSA
DHe
• CD efficiency lower than predicted by CURRAY ray-tracing code (Mau) and slightly lower than AORSA full-wave code (Jaeger).
• Density-normalized current drive efficiency same as at lower densities in D and He ( = 0.03 x 1019 A•m-2•W-1)
• Double-null and single-null diverted configurations give similar efficiencies.
20022003
2004
HHFW CD efficiency, referenced to total antenna power, is somewhat lower than predicted
Ryan NSTX Results 2004
Te(0) = 2 keVkz = 7.6 m-1
2.0
1.5
1.0
0.5
0.00.60.50.40.30.20.10.0
time (s)
6
5
4
3
2
1
0
Central Electron Temperature
-30º-90º
ohmic
112326112327112328112336
6
5
4
3
2
1
00.60.50.40.30.20.10.0
time (s)
6x104
5
4
3
2
1
0
Total Stored Energy
-30º-90º
ohmic
112326112327112328112336
Line-average density3.0x1015
2.5
2.0
1.5
1.0
0.5
0.00.60.50.40.30.20.10.0
time (s)
6
5
4
3
2
1
0
ohmic
-30º-90º
112326112327112328112336
HHFW operation at kz = 3 m-1 failed to heat central electrons
• CURRAY and AORSA calculations predict greater current drive efficiency for Te(0) ~ 2 keV.
• Plasma was pre-heated to Te(0) ~ 2 keV with 2.5-3 MW of HHFW for 100 ms at -90º phasing (-7.6 m-1).
• Fast switching to 1.7 MW at -30º (-3 m-1) caused a rapid collapse of Te and an increase in <ne>.
Ryan NSTX Results 2004
RF
Po
we
r (M
W)
RF
Po
we
r (M
W)
RF
Po
we
r (M
W)
-90º -30º
Density Contours From Reflectometer
Onset of rf steepens edge profiles
Phase shift has little effect on edge profile
Driven H-mode and NBI-Combined Heating Summary
Preliminary Data - Leblanc
• HHFW Driven H-mode plasma operational envelope expanded
– Ip ≈ 0.6-0.8 MA, BT ≈ 0.45 T, medium density DND
– k// = 14 and 7 m-1 at Ip = 0.6 MA
– k// = 14 m-1 at Ip = 0.8 MA
• Combined HHFW-NBI operation
– Developed 2-beam reduced energy scenario compatible with HHFW antenna operation
– NBI into HHFW pre-heated plasmas
• Wmhd and neutron rate increases observed
• Low efficiency
– HHFW into NBI-drive H-mode plasmas
• Wave do no seem to reach plasma core
BPL-NSTX-Res-Sep-2004
HHFW H-mode at 0.7 MAHHFW with beam blips, k// = 14 m-1, 1.5 MW
BPL-NSTX-Res-Sep-2004
HHFW Driven H-mode at 0.8 MAHHFW only, k// = 14 m-1, 2.0 MW
BPL-NSTX-Res-Sep-2004
NBI Pulses into HHFW Heated PlasmaObserved Wmhd and Neutron (Sn) Increases
Sn increase larger than for Wmhd
BPL-NSTX-Res-Sep-2004
HHFW into NBI Driven H-mode PlasmaSmall Effects On Wmhd and Neutron (Sn) Are Reproducible
Seem more compatible with edge effects than heating
BPL-NSTX-Res-Sep-2004
