charge exchange spectroscopic diagnostic for the tj-ii josé miguel carmona torres laboratorio...
DESCRIPTION
Motivation DNBI has been installed on TJ-II CXRS local measurements of Ion Temperatures Poloidal & Toroidal Velocities Electric fields Impurity densities using experimental data + simulation code A lot of work to do…TRANSCRIPT
Charge Exchange Spectroscopic Diagnostic for the TJ-II
José Miguel Carmona Torres
Laboratorio Nacional de FusionEURATOM-CIEMAT
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Motivation
•DNBI has been installed on TJ-II
•CXRS local measurements of
IonTemperatures
Poloidal & ToroidalVelocities
Electric fieldsImpurity densities using experimental
data + simulation code
A lot of work to do…
Contents
• Motivation• Diagnostic Neutral Beam Injector• Stellarator TJ-II• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Stellarator TJ-II
•An Heliac Flexible device•Minor and mayor radii from 0.22 m to 1.5 m•B created by external coils (Bmax=1 T)•ECRH y NBI heating•Plasma cross section is bean-shaped
TJ-II Mag. flux surfaces for 2 diferent magnetic configurations. Magnetic Islands appers on diferent configurations as 58_83_61 .
Fully tridimensional plasma structure with easy access to portholes
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Diagnostic Neutral Beam Injector
DNBISECTOR
A7
TOPPORTHOLE
NBI_1 NBI_2
Scheme of DNBI
Picture of DNBI installed in the TJ-II
Dnbi Parameters-Focal length 170 cm-Pulse length 5 ms -Beam Energy ~30 KeV-1/e divergence <0.7 º-1/e radius at focus ~21 mm-Extracted ion current 4 A/cm2
-Beam Components (H,H2,H3) ~90%, ~8%, 2%
DNBI sector A7, mounted on a support structureRev. Sci. Instrum. 75, 3499 (2004)
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Multichannel Diagnostic
Canon 85 mmF/1.2 l USM
12 fiber arrayFiberguide Industries
diameter 600m
Holospec Spectrographf/1.8 high resolution and high dispertion grating
CCD Pixis Princeton Instrum. back-illuminated 1024 x 1024 Pixels (13 m)
J.M. Carmona et al. HTTP Conference 2006, Virginia, USA
*
* Ilustration from Alcator
Multichannel Diagnostic
J.M. Carmona et al. Rev. Sci. Instrum. 77, (2006) In press
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Beam CharacterizationHypothesis:• Homogeneos source• Elemental beams emitted from source dS• of neutrals Termal Distrib.Multiple sum of coaxial Gaussians
V
2
2
exp)(),(zrzgrzzj f
b
b
t
b
TE
vv
2
2
• Convolution between Gaussians and Q(rz)=Q(r1-z/zf)
20,exp0,),( rzj
Izjrzj
j(z,0) I
a2
z*2
z2 1 exp a2
z*2
Neutral beam profile in vacuum:
2
*
2
2
*
2 0,expexp1),( 2
2
rzjIz
azz
aIrzj
P. Bosshard Thesis, TCV
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Interaction and corrections
totimpimp
totpp
b
eee nn
vv
n
•Beam attenuation by means of collisions
z
z
dzzIzIdzI
dI
0
exp)(/)( 0 attenuation coefficient
Proton and Imp.densities?
eeff
impeeff
p nZZ
Znn
ZZZ
n)1(
11
Interaction and corrections•Some corrections on are needed ve
ADAS databaseVneutrals<<Velectrons
f (Te)
•Vneutrals=30 KeV Vneutrals106 m/s Velectrons107 m/s
e
be
b
e
e
eber T
EvMT
mEvvv 132
b
e
Mmwith
32
effreff TvE 2/32/1 2
2/1 ebeeff TETT
J.M. Carmona et al. EPS Conference. Tarragona 2005
Contents
• Motivation• Stellarator TJ-II• Diagnostic Neutral Beam Injector• Multichannel Diagnostic• Beam Characterization• Interaction and corrections• Estimation of Counts
Estimation of Counts
•Photons? Charge-Exchange
h (CVI 87)
•Number of photons
PCX
14
Aij(8 7)
Aijv i N idl
i
N imp t sist
Branching RatioRate coefficients for 30, 15, 10 KeV Optical window, lens, fibers, coupling,
spectrograph and CCD total efficiency
Some results
An ‘artistic view’ of the simulation code, showing attenuated (red) vs non-attenuated beam (green)
First measurements are expected to be obtained in the next campaign