longwen yan, experimental progress on hl-2a, 6-8 jan. 2014, tsinghua university, beijing 1/29 hl-2a...
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Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 1/29
HL-2A
Southwestern Institute of Physics, Chengdu, China
Experimental Progress on HL-2A
HL-2A Team (Presented by Longwen Yan)
The Second A3 Foresight Workshop on Spherical Torus
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 2/29
HL-2A
HL-2A tokamak
Diagnostic development
Confinement improvement and transport
Energetic physics and MHD activity
Turbulence and zonal flows
Summary
Outline
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 3/29
HL-2AHL-2A tokamak
•R: 1.65 m
•a: 0.40 m
•Bt: 2.7 T
•Ip: 450 kA
•ne: ~ 6.0 x 1019 m-3
•Te: ~ 5.0 keV
•Ti: ~ 2.8 keV
Auxiliary heating systems ECRH/ECCD: 3 MW: 60.5 MW/68 GHz/1 s 2 MW: 21 MW/140 GHz/3 s Modulated f=10~30 Hz; Amp. 10~100% NBI: 3 MW/55 kV/2 s (5 MW/80keV) LHCD: 2 0.5 MW/2.45GHz (2 MW/3.7GHz)
Fuelled system (H2/D2):
Gas puffing (LFS, HFS, divertor) Extruded PI (40 pellets/LFS, HFS) SMBI (LFS, HFS) LFS: f =10~60 Hz, pulse>0.5ms Gas pressure: 0.3-3.0 MPa HFS: f = 1-5 Hz, 0.2-1.0 MPa
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 4/29
HL-2A
HL-2A tokamak
Diagnostic development
Confinement improvement and transport
Energetic physics and MHD activity
Turbulence and zonal flows
Summary
Outline
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 5/29
HL-2AComparison of MSE spectral broadening
0.0
0.5
1.0
0.0
0.5
1.0
0.0
0.5
1.0
659.5 660 660.5 661 661.5 662 662.50.0
0.5
1.0
wavelength (nm)
Rel
ativ
e in
tens
ity (a
rb.u
nits
)
experimentfitting
experimentfitting
-
(a)
(b)
(c)
(d)
R=1.67m
R=1.67m#20239
R=1.95m
#20239
+
+ -
- +
+ -
R=1.95m
simulation
simulation Simulation parameters
• Beam dissipation d≈1.0° • Lens size=37mm • Energy dissipation dv=2%
Fitted functions
• I0 is intensity of central wavelength
0 is Stark splitting at central wavelength and σ is spectral width
2
20
2
)(
0)(
eII
Jiang N. et al 2013, CPL30, 065201
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 6/29
HL-2A
1.6 1.65 1.7 1.75 1.8-2
0
2
4
6
8
R (m)
Pit
ch a
ngle
(o )
t=420 mst=460 mst=500 ms
# 22196
Profiles of magnetic field pitch angle
Radial profiles of magnetic field pitch angles slightly increase with time, indicating current profiles to be peaking gradually
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 7/29
HL-2AFILD diagnostics successful on HL-2A
Shot 22614 Bt=1.34 TFrame f=500 fpsProbe at R=2.13 m
Current flattop during NBI Plasma disruption with NBI Flattop phase: Fast ion loss energy 40-50 keV
and pitch angle 630. Disruption phase: Fast ion loss energy and
pitch angle change with magnetic perturbation rather largely.
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 8/29
HL-2A
Pedestal structure during an ELM measured by a new microwave reflectometry with high spatiotemporal resolutions
Pedestal structure evolution during ELM
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 9/29
HL-2A
HL-2A tokamak
Diagnostic development
Confinement improvement and transport
Energetic physics and MHD activity
Turbulence and zonal flows
Summary
Outline
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 10/29
HL-2ABasis of confinement and transport
• Particle ITB observed in HL-2A for the first time (Xiao W. W. 2010, PRL. 104 215001)
• NLT effect induced by SMBI fuelling and ECRH switching off (Sun H.J. et al. 2010, PPCF 52 045003; Sun H.J. et al. 2012 NF 51, 113010)
• Turbulence and ELM characteristics (Duan X.R. 2010, NF 50, 095011; Yan L.W. 2011, NF 51 094016)
• ELM mitigation by SMBI/CJI fuelling succeeded on HL-2A for the first time, and confirmed by KSTAR and EAST (Xiao W. W. et al. 2012 NF52, 114027 )
• Duan X.R., NF 49 (2009) 104012
• Xiao W. W. 2010, PRL. 104 215001
• Zhong W.L., PoP 17, (2010)112307
• Liu Yi, PRE, 84 (2011) 016403
• Huang Y., NF 52 (2012)114008
20 25 30 350.8
1
1.2
1.4
1.6
1.8
2
r(cm)
ne(1
019
m-3
)
250ms420ms480ms520ms
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 11/29
HL-2A
140 160 180 2000
200
400
600
800
1000
1200
Ip(kA)
f EL
M(H
z)
w/o SMBIwith SMBI
HL-2A
ELM mitigated by SMBI successfully
3.5-2/ff 0ELM
SMBIELM
ne=1.8~2.3×1019m-3
Paux=0.9-1.4 MWXiao W. W. et al. 2012 NF52, 114027
Pedestal density gradient drops after SMBI fuelleing, indicating particle confiement degeneration
(a)
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 12/29
HL-2AELM mitigated by CJI better
2.2/ff 0ELM
CJIELM
0.38/II 0ave
CJIave Cluster jet injection
(CJI ) mitigates ELM instability with better effect than SMBI
1 1.5 2 2.5 3 3.50
0.2
0.4
0.6
0.8
1
f ave
/ f 0 ave
I av
e / I0 a
ve
SMBICJI
Duan X. R. 2013, NF53, 104009
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 13/29
HL-2AL-I-H transition by sawtooth crashes
• L-H transition may be
triggered by sawtooth crashes
• Plasma density and energy
increase with time
• The frequency of I-phase
oscillations decrease from
2.2kHz, 1.9kHz to 1.4 kHz.
• The I-H transition
successfully after the fourth
sawtooth crash
600 620 640 660 680 700 720 740 760
0.1
0.2
0.3
0.4
Time (ms)
I-D
,d
iv (
a.u
.)
0
0.2
0.4
0.6
0.8
1
1.2
I-s
x (
a.u
.)
1.5
2
2.5
3
0.82
0.30
0.80
0.67
0.18
0.50
0.60
0.74
L-mode
(b)
2.2 kHz 1.9 kHz 1.4 kHz
(c)I-phase
WE (10 kJ)
ne(1019 m-3)
type-III ELMs type-III ELMyH-mode
0.40(a) # 19720
Liu C. H. et al. EPS2013, P5.157
Zhao K. J. et al. NF 53 (2013) 123015
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 14/29
HL-2AELM-free H-mode with EHO-like
• EHO-like mode leads to density rate dropping and turbulent particle flux rising in SOL
• This mode located near
r/a=0.94) with f=5-10
kHz and mode number
m/n=3/1
• The EHO appears on D
and SXR emission
Zhong W. L. 2013, NF53, 083030
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 15/29
HL-2AStrong particle convection after SMBI
Yu D. L. 2012, NF 52, 082001
• The density at outer channels (Z = -17.5, 24.5 cm) drop after a few milliseconds fuelled by SMBI
• The density at central region (Z = ±3.5 cm) sustains about 30 ms to be dropping
• The density gradually peaks after SMBI (h).
• The results indicate that strongly inward convection exists after SMBI
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 16/29
HL-2AImpurity transport in Ohmic and ECRH
0
0.2
0.4
0.6
0.8
1.0
1.2
0
2
4
6
8
0 10 20 30 40 50
CV
(10
-6W
cm-2
)
CIV
(10
-5W
cm-2
)
V=-1m/s
CIVCV(a) Ohmic
r (cm)
0
1
2
3
0
1
2
3
4
0 10 20 30 40 50
CV
(10
-6W
cm-2
)
CIV
(10
-4W
cm-2
)
r (cm)
V=7m/s
V=-1m/s
CIV
CV
ECRH
• There is a good agreement between the simulation (lines) and the experiments (symbols) results with diffusion D = 0.6 m2/s and inner convection V(a) = -1 m/s in Ohmic plasma
• The strong decrease of the CV intensity compared with CIV in ECRH can only be reproduced with outer convection V(a) = 7 m/s
(b)
Cui Z. Y. et al 2013, NF 53, 093001
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 17/29
HL-2A
HL-2A tokamak
Diagnostic development
Confinement improvement and transport
Energetic physics and MHD activity
Turbulence and zonal flows
Summary
Outline
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 18/29
HL-2ABasis of Energetic Physics
• Beta-induced Alfven eigenmode (e-BAE) by energetic electrons was identified for the first time
• Multiple BAE modes are investigated• Ion and electron fishbones were
confirmed• The frequency jump of e-fishbone
was found uring ECRH. • Long-lived runaway electron beam
was observed during major disruptions (Zhang Y.P., PoP 19 (2012) 032510)
• The fast ion slowing-down time is in agreement with classical theoretical prediction (Zhang Y.P., PoP 19 (2012) 112504)
time (ms)
f (kH
z)
200 400 600 800 1000 12000
10
20
30
-0.50 0.5
0.5
1
e-BAE
ECRH
Mir (a.u) NBI
m-BAE
a( )
b( )
c( )
ne (1019 m-3)
TMnoise
Chen W., NF 49 (2009) 075022Chen W., NF 50 (2010) 084008Chen W., PRL 105 (2010)18500Chen W., NF 51 (2011) 063010
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 19/29
HL-2ABeta-induced Alfvén acoustic eigenmode
• BAAE with f = 15-40 kHz identified by frequency up-chirping, consistent with the solution for Alfvén-acoustic continuum
• A clear spectrum splitting is first observed on BAAE
Shot 10391
•Ip = 170 kA
•Bt = 1.4T,
•qa 4.0,
•Te 1.0 keV
•Ti 0.8 keV
•PNBI =0.6 MW
Alfvén-acoustic mode
Tearing mode
Splitting
Liu Yi, et al 2012, NF 52 074008
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 20/29
HL-2AFrequency jump of e-fishbone mode
Ip=155-160 kA
ne=0.3~0.7×1019m-3
BT=1.2-1.22 T
ECRH deposited
inside q=1 surface
• Both low and high frequency branches are observed• The high frequency branch could be observed only if
PECRH > 0.8 MW
• Frequency jump gap increases with the ECRH power • Low & high frequency modes are m/n = 1/1 and 2/2
Electron fishbone frequency jump was observed in the low density ECRH plasma, where the trapped particles are dominant.
Yu L. M., et al NF53, 053002
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 21/29
HL-2ALow-frequency multimode coexistance
• Low frequency multiple Alfven modes coexist during high power ECRH.
• Mode frequencies decrease with ne
and slightly increase with Te, finally
overlap with each other.
Ip= 155-160 kA Bt = 1.2-1.4 T
ne < 1.4 × 1013cm-3 PECRH > 0.6 MW
m/n = 4/2, 5/2, 3/1, 6/2, 4/1
Ding X. T. et al 2013 NF 53 043015
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 22/29
HL-2ALong lived mode & its control
LLM suppressed by ECRH or SMBILLM observed during NBI with weakly reversed or broad low magnetic shear
• LLM degrades plasma confinement and enhances fast ion loss
• LLM oscillation in LFS is stronger than that in HFS
Deng W. et al. 2014, NF 54 013010
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 23/29
HL-2A
HL-2A tokamak
Diagnostic development
Confinement improvement and transport
Energetic physics and MHD activity
Turbulence and zonal flows
Summary
Outline
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 24/29
HL-2ABasis of edge turbulence and ZFs
• The toroidal symmetries of GAM
and LFZF were confirmed on HL-
2A for the first time
• Turbulence nonlinear energy
transfer was identified for the first
time
• Two types of LCO were founded
• Three dimensional structure of
filamentary plasma was studied
•Zhao K.J., PRL 96 (2006) 255004
•Yan L.W., NF 47 (2007) 1673
•Zhao K.J., PoP 14 (2007)122301
•Lan T., PoP 15 (2008) 056105
•Zhao K.J., NF 49 (2009) 085027
•Cheng J., NF 49 (2009) 085030
•Liu A.D., PRL103 (2009) 095002
•Zhao K.J., PPCF 52 (2010)1240081 10 100
0
2
4
6
8
pow
er(a
,u)
f(kHz)
1 10 1000
1
2
3
pow
er(a
,u)
(a)
(b)
GAM
q=6.2
q=5.2
q=3.5
380kW
680kw
GAM
LFZF
LFZF
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 25/29
HL-2ANonlinear energy transfer
• Turbulent kinetic energy was transferred into LFZFs and GAMs
• the energy transferred into LFZFs increases with heating power
• Turbulence drives low frequency sheared flows
1 1
1
*( ) Rev f f f ff
T f v v v
Nonlinear energy transfer rate
Xu M. et al. 2012 PRL 108, 245001
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 26/29
HL-2ATwo types of I-phase trajectory
• Trajectories of the system in phase space of normalized radial electric field Er and RMS of the density envelope (20-100 kHz) measured at Δr =
−5 mm for discharge with L-I-H transition (a) and L-I-L transition (b).
Cheng J. et al. 2013 PRL. 110 265002
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 27/29
HL-2A
• Eddy amplitude increases firstly, it is stretched and split into two islands by strong E×B flow, finally plasma filaments are ejected into SOL
• The flow shearing time at filamentary birth position is identified to be close to the filament generation time (~4 s )
r (mm)
( s
)
-10 -5 0 5 10 15
-8
-6
-4
-2
0
2
-0.50.51.52.5
0.1
0.2
0.3
I s (A
)
-40 -20 0 20 40
0
1
2
3
(s)
Rs' (
108 m
s-2)
(c)(a)
(b) = -4 s
E (10
5s
-1)
Filament generation near the inner LCFS
-10 0 100
10
20
30
-10 0 100
10
20
30
r (mm)
Polo
idal
(m
m)
-10 0 100
10
20
30
r (mm)-10 0 10
0
10
20
30
r (mm)-10 0 10
0
10
20
30
Polo
idal
(m
m)
-10 0 100
10
20
30 (a) (b) (c)
(d) (e) (f)
-8s -6s -4s
-2s 0s 2s
Ip = 160-170 kA
Bt =1.8-1.9 T
ne= 1.8-2.5×1013cm-3
q95= 4.5-5.5
r/a = 0.96-1
Dependent on the significant parallel correlation
Spatiotemporal evolution of E×B shearing rate
trE )/Br/E(
Cheng J. et al 2013 NF53, 093008
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 28/29
HL-2ASummary• MSE, FILD, and MWR with high resolutions succeeded• ELM frequency rises to a factor of 2-3.5 but its amplitude drops
38% by using SMBI/CJI mitigation.• CJI is more efficient than SMBI for the ELM mitigation• L-I-H transition can be induced by sawtooth crashes• ELM-free H-mode observed with m/n=3/1 EHO mode of 5-8 kHz• The SMBI fuelling efficiency is enhanced by strong convection• The strong decrease of the CV intensity compared with CIV in
ECRH needs a outer convection velocity of 7 m/s• Frequency jump of e-fishbone and LF multimode coexistence• Long lived modes have been controlled by ECRH and SMBI• Turbulent energy transferred into ZFs & GAM by nonlinear
process• Normalized Er ~ 1 is critical to trigger L-I-H transition• Plasma filament just generated at the inner LCFS
Longwen Yan, Experimental Progress on HL-2A, 6-8 Jan. 2014, Tsinghua University, Beijing 29/29
HL-2A
Thank you for your attention !
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