Internal electrostatic and magnetic measurement in SUNIST
description
Transcript of Internal electrostatic and magnetic measurement in SUNIST
Department of Engineering Physics, Tsinghua University, Beijing, P. R. China
Internal electrostatic and magnetic measurement in SUNIST
S. Chai,W. H. Wang
* E-mail: [email protected]
The Second A3 Foresight Workshop on Spherical Torus, Jan. 6-8, 2014, Tsinghua University, Beijing, China
Layout of the Windows
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
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0.1
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R (m)
Z (m
)
The magnetic probesMoveable multi-probes
Moveable inner Langmuir& magnetic probe
Langmuir probes
Poloidal magneticprobes array
Toroidal magnetic probesarray & flux loops
Top view of SUNIST
Langmuir Probes (1)
• Probe design--Total movable distance
• ~13 cm ( 0.78a ~ 1.35a)
--Tips configuration• 4 tips: 2 float, 2 connected for Isi
• Material: Mo
• Typical results-- ne, Te, fp, and ff
-- Shot by shot scanning
Wang W. H., et al., PPCF 2005
Tips configuration
Typical results
Picture of the probe
• An integrated probe-- A magnetic probe-- A 4 tips Langmuir probe set
• Purpose-- To get local plasma pressure and magnetic pressure simultaneously
• Future plan-- Smaller size, more “local”
Moveable Langmuir-magnetic Probe(2)
Raw signals from the Langmuir-
magnetic probe
The moveable Langmuir-magnetic
probe
-40-20
0
I P (k
A)
Shot 130108002
-505
VF2
(V)
0102030
VF1
(V)
0
100
V+ (V
)
02040
I SI (m
A)
30 35 40 45 50 55 60 65 70-5
0
5 x 10-4
Time (ms)B
P (a
.u.)
2013
Moveable Multi-probes (3)
Langmuir Probe
Magnetic Probe
Retarding-field Energy Analyzer ( RFEA )
Drawing of moveable multi-probes
Parameters of 4 tips Langmuir probe:L=3mm,d=1mm ,Ap=10.21mm2
Parameters of magnetic probe:N=310, d=10mm S=78.5mm2 NS=0.0243m2
Entrance slit: 5mm*0.4mmMesh Aperture: 0.2mm
38*20*20mm
Retarding-field Energy Analyzer
Principle of the RFEA(1)
(1):Ion velocity distributions at the tokamak edge; R.A.Pitts; 31 May 1991 (2):W.H.Wang;
The relationship between collected Isi and scan potential:
)(21)(
).()(exp21)(
psTiii
pipsTii
VcATenIVI
VkTVZecATenVI
Volt-ampere relationship(2)
-250V 300V 27V
Test Result
a
b
Vf1
Vf2
Isi
A Experimental result of magnetic probe; b Experimental resultof Langmuir probe;
Location of probe Bp10
*100 mA
*20 V
*20 V
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Further work
RFEA: radial profile of TiMagnetic Probe: radial profile of BpLangmuir probe: radial profile of Ne,Te
Bootstrap current density:
Moveable multi-probes Bootstrap current
John Wesson, 《 TOKAMAK 》 , chapter 4.9
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SummaryInternal electrostatic and magnetic measurement in SUNIST includes :1. A set of Langmuir probe: On one side of the vacuum
chamber2. Toroidal and poloidal magnetic array & flux loops: EFIT,
displacement, feedback control…3. A set of moveable magnetic & Langmuir probes: On the
other side of the vacuum chamber4. A set of moveable multi-probes: Profile of Te, Ti, Ne,
bootstrap current…
Thank you for your attention!
狭缝的尺寸:足够小,不大于 2 倍的鞘层厚度, 6-8 倍的德拜长度SUNIST 上的一些参数:Te=20eV , Ne=3*1018m-3
钨钼合金(绝缘、抗热震、高热材料,但难开缝,需用等体切割) 厚度 0.5mm ,切口长 * 宽 ( 3~5mm*0.1mm )栅网孔径:要求离子通过时整个栅网等电位,
ni’ 为分析器内部离子密度,由于分析器内密度远小于外部,所以这个条 件比较容易满足。材料为钼丝,网孔径 200um收集板:纯铜电源:低频功率源 频率高于 50kHz ,功率在几十 kw 量级,扫描电压正负250V HA-405A 高压放大器 最高频率500kHz ,扫描电压 0~400V
技术难点
Entrance slit: 5mm*0.4mmMesh Aperture: 0.2mm
聚四氟乙烯 Teflon
Here, plasma potential outside the RFEA; ni ion density; Cs the ion-acoustic velocity; A is the slit window area; TT is the total transmission coefficient. So
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磁探针测得的磁场变化情况
0 10 20 30 40 5012
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Te [e
V]
Distance [mm]
Triple Probe Te, Ne
-0.03
-0.028
-0.026
-0.024
-0.022
-0.02
-0.018
-0.016
-0.014
-0.012
-0.01
-0.008
-0.006
-0.004
-0.002
Ne [1
018
m-3
]
TeNe
0 10 20 30 40 50160
165
170
175
180
185
190
Distance [mm]
Bp
[Gs]
Triple Probe (Bp)
磁探针测得的磁场变化图像T=47~52ms 测得的 Ne 、 Te 和 Bp 的值
Parameters of SUNIST R0 0.3 m
a 0.23 m
BT 0.15 T
ΨOhm 60 (37) mV.s
IP 50 (70) kA
Pulse length 15 (20) ms
ne ~1×1019 m-3
Te ~100 eVRed: achieved
Diagnostics and heatinga. Quadruple probe ×1
b. B-dot probes ×15, flux loops ×13c. Internal composite probe×1
d. Interfermetor(94 GHz)×1e. Reflectometer(26~40 GHz)×1
f. Radiometer(2~12 GHz)×1g. Spectrometer(380~600 nm)×2
h. Fast camera(5130 fps)×1i. Hard X-ray, NaI×1,CdZnTe×2
j. ECH(5 GHz/200 kW , under test)×1
k. AWH(0.4~1 MHz/400 kW)×1
j
kk
k k
a
cd, g, i
e, f, h
Progress of AW experiments
TMPCryogenic Pump,
Ion Sputtering Pump
Fast Visible Camera
Photodiodes, NaI Detector
Piezo-valves
Toroidal Field Coils
94 GHz Interferometer
Antenna 4
Antenna 3Antenna 2
Antenna 1
Antenna Strap
FeedthroughBN Limiters
Plasma Torus
CdZnTe Detector
2.45 GHz Pre-ionizer
Topview of SUNIST Antennas and the plasma torus