Fast-ion Dα spectroscopy diagnostics in KSTAR · Introductions Experimental setup ID: #71 EMCCD...
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Fast-ion D α spectroscopy diagnostics in KSTAR J. W. Yoo a , Junghee Kim a , J. H. Lee a , Y. U. Nam a , S. G. Oh b , J. S. Kang a , M. W. Lee a , J. S. Ko a , W. -H. Ko a , L. Jung a and B. H. Park a a National Fusion Research Institute, Daejeon, Korea b Ajou University [email protected] 1A 1C 1B ND filter CII CII Beam emissions Bremsstrahlung • In KSTAR FIDAdiagnostic system has been developed and the commissioning has been performed since 2018 KSTAR experimental campaign. • It consists of the grism, two tele-lens sets, blocking strip and EMCCD. The temporal, spectral and spatial resolutions of the spectrometer are 20 msec, 0.0215 nm and 4-10 cm respectively. • FIDASIM calculations has been commissioning with KSTAR spectrometer data to precisely evaluate FIDA signal. Introductions Experimental setup ID: #71 EMCCD (Andor iXon Ultra 888) VPH Grism *Initial spectrometer system has been made by Prof. S.G. Oh and students (Ajou Univ.). Imaging lens Collimating lens Slit Fiber-Entrance ND-filter strip Front optics Fiber-bundle holder FIDA02 J-port cassette: Integrated Optics module FIDA01 FIDA01 CH R [cm] 1 224.71 2 220.28 3 217.00 4 213.11 5 209.52 6 206.69 7 203.90 8 201.03 9 198.79 10 196.32 11 193.75 12 191.28 13 189.32 14 186.93 15 184.93 16 182.92 FIDA02 CH R [cm] 1 227.56 2 211.87 3 199.34 4 189.03 5 179.17 6 171.61 7 165.68 8 161.07 9 157.35 10 154.5 Position of LOS Absolute calibrations of raw spectra for comparisons of intensity ≈ ∗ Conversion from digitized counts to photon radiance with, , , , , , , , , , , Δ, ℎ , Δ, , , . [ ℎ 2 ] FIDA measurement 0 m 2 /s 0.3 m 2 /s 0.5 m 2 /s 1 m 2 /s 0 m 2 /s 0.3 m 2 /s 0.5 m 2 /s 1 m 2 /s Z eff = 2 Z eff = 3 Z eff = 4 NBI 1 NBI 2 FIDA01 FIDA02 I P and B T Non-charge exchange component (OV, CII, OIV..) can be subtracted by beam modulations. Weight function depends on, Minimum energy and Gyro-angle weight [1] = − = || + ⊥ − [1] Luo Y, Heidbrink W W, Burrell K H, Kaplan D H and Gohil P 2007 Rev. Sci. Instrum. 78 033505 [2] W. Heidbrink, D Liu, Y. Luo, E. Ruskov, and B. Geiger.Commun. Comput. Phys., 10(10):716–741, 2011. [3] O. Meneghini et al., Nucl. Fusion 55, 083008 (2015). [4] W W Heidbrink et al., PPCF 49 1457-1475 (2007) [5] Luo, PhD thesis (2007) Geometric weighting 18602 at 13.65 s R, Z = 190 m, -0 m BEAM A, B, C (100, 70, 70 keV) Fast ion distribution function calculated by NUBEAM convolutions a=0.065pi a=0.2pi vertical tangential a, angle between b⊥1 and LOS at b∥, b⊥1 plane Examples of weighting function for KSTAR = න , ⅆ ⅆ FIDASIM [2] calculations Modelling setup FIDASIM with Preset Models beam and halo neutrals, calculates VBE, cx probabilities, weight function, active FIDA radiance using sightline geometry Preset Neutral beam geometry Equilibrium Plasma profiles TRANSP or NUBEAM (OMFIT [3]) Theoretical fast ion distribution functions F (E, p) FIDA and NPA 2019 FIDA01 geo, equilibrium with CCW B T and I P (21747Z35) Comparison with the measurements (MSE LOS) Spectra measured by MES LOS w/o modulation @ 2.00-2.35 s FIDASIM with neutral beam current fraction (0.467, 0.374, 0.159) ↓ BES CII CII BES CH01 R = 1748 mm CH20 R = 2175 mm FIDA01 FIDA02 MSE CH16 ~ CH01 CH01 ~ CH10 CH01 CH20 Geometrical inputs for FIDASIM → Comparison with physical parameters Sensitivity study with Z eff and D f FIDA spectrometer Calibration of each line of sight Wavelength calibrations Predictions of E-p space sensitivity (weight function) Count [a. u.] -0.0162x+667.5170 -0.0162x+667.5113 -0.0162x+667.5139 -0.0162x+667.4823 -0.0162x+667.4634 -0.0162x+667.4182 -0.0162x+667.3651 -0.0162x+667.3206 Target wavelength Ne (653.29 nm) H α (656.27 nm) D α (656.09 nm) Ne (659.89 nm) Radiance [Ph/(m2*nm*s*sr] Application for each CH. For the sensitivity study, effective Z, profile shape of Z eff , fast ion diffusivity and current fraction are scanned. Especially large values of Z eff enhances bremsstrahlung emissions signal to noise ratio is gone bad. Bremsstrahlung, one order larger than FIDA intensity (∝ n e 2 ) Since KSTAR FIDA systems in mid-plane and tangential array (a ~ 0.5 pi) Convolution shows the narrower region of the E-p coverage. Patch panel FIDA (fast ion D α ) system consists of two mid-plane tangential arrays. J-port cassette: Integrated Optics module shared with visible spectroscopy and filter scope Integrated FIDASIM modelling platform (handling the profile data + TRANSP outputs) is necessary. ⓐ ⓑ ⓒ ⓐ FIDASIM run ⓑ FIDASIM calculation results with FIDA01 It shows blue shifted BES and is compared with FIDA measurements but it is hardly matched in one time calculation. Need iterations ⓒ comparison with MSE measurement and the calculations calculation is qualitatively matched with MSE measurement. Since MSE and FIDA view aligned looking at beam line in opposite side, this can be good base material for reliability check. ⓓ neutral density calculations with beam grid (FIDASIM inputs) at FIDA focal points ⓔ neutral density of each component along the beam lines (X beam ) ⓕ neutral density at FIDA LOSs ⓕ Neutral density at focal points of FIDA FIDA01 FIDA02 ⓓ ⓔ FIDA01 FIDA02 1. Spectroscopic measurements in beam into gas and plasma discharges will be performed for the reference spectra. 2. Additional FIDA array (FIDA02) will be introduced in 2019 campaign to span the detectable fast-ion phase-space. 3. FIDASIM iteration is necessary with newly acquitted data. 4. To expand FIDA operational range of fast-ion phase-space, optical alignment is under discussion. 5. To understand fast ion physics, various operation scenarios and relevant MHD instabilities will be investigated. Summary FIDA density with heating in time trace [4] Scaling study with FIDA density [5] FIDA density = FIDA intensity/beam neutral density ∝ Fast ion density (∝ P inj f(T e )/n e )∝ Fast ion pressure FIDA density profile seems to be qualitatively and quantitatively matched with shape of fast ion pressure (TRANSP) Single energy FIDA profiles 661 nm ~70 keV P f profile comparison in DIII-D [3] 661 nm ~ 653 nm Fast ion pressure calculated by TRANSP FIDA density 21747Z35 References Acknowledgments The authors would like to acknowledge the KSTAR team and appreciate Alvin Garcia for useful comments.
Transcript of Fast-ion Dα spectroscopy diagnostics in KSTAR · Introductions Experimental setup ID: #71 EMCCD...
Fast-ion Dα spectroscopy diagnostics in KSTAR
J. W. Yooa, Junghee Kima, J. H. Leea, Y. U. Nama, S. G. Ohb, J. S. Kanga, M. W. Leea, J. S. Koa, W. -H. Koa, L. Junga and B. H. Parka
aNational Fusion Research Institute, Daejeon, KoreabAjou University
1A
1C
1B𝐼𝑝
𝐵𝑡
ND filter
CII
CII
Beam emissions
Bremsstrahlung
• In KSTAR FIDA diagnostic system has been developed and the commissioning has been performed since 2018 KSTAR experimental campaign.
• It consists of the grism, two tele-lens sets, blocking strip and EMCCD. The temporal, spectral and spatial resolutions of the spectrometer are 20 msec, 0.0215 nm and 4-10 cm respectively.
• FIDASIM calculations has been commissioning with KSTAR spectrometer data to precisely evaluate FIDA signal.
Introductions
Experimental setup
ID: #71
EMCCD
(Andor iXon Ultra 888)
VPH Grism
*Initial spectrometer system has been made by Prof.
S.G. Oh and students (Ajou Univ.).
Imaging lens
Collimating lens
Slit
Fiber-Entrance
ND-filter strip
Front optics
Fiber-bundle holder
FIDA02
J-port cassette: Integrated Optics module
FIDA01
FIDA01
CH R [cm]
1 224.71
2 220.28
3 217.00
4 213.11
5 209.52
6 206.69
7 203.90
8 201.03
9 198.79
10 196.32
11 193.75
12 191.28
13 189.32
14 186.93
15 184.93
16 182.92
FIDA02
CH R [cm]
1 227.56
2 211.87
3 199.34
4 189.03
5 179.17
6 171.61
7 165.68
8 161.07
9 157.35
10 154.5
Position of LOS
Absolute calibrations of raw spectra for comparisons of intensity
𝑳𝝀 ≈𝑷
𝑨𝐜𝐨𝐬𝜽𝜴𝚫𝝀𝚫𝑻∗ 𝑭
Conversion from
digitized counts to photon radiance with,
𝐴, 𝑠𝑜𝑢𝑟𝑐𝑒 𝑎𝑟𝑒𝑎, 𝑃, 𝑑𝑖𝑔𝑖𝑡𝑖𝑧𝑒𝑑 𝑐𝑜𝑢𝑛𝑡𝑠 ,
𝐿𝜆, 𝑠𝑝𝑒𝑐𝑡𝑟𝑎𝑙 𝑟𝑎𝑑𝑖𝑎𝑛𝑐𝑒, 𝜃, 𝑣𝑖𝑒𝑤𝑖𝑛𝑔 𝑎𝑛𝑔𝑙𝑒, 𝛺, 𝑠𝑜𝑙𝑖𝑑 𝑎𝑛𝑔𝑙𝑒,
Δ𝜆, 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ 𝑏𝑖𝑛,
Δ𝑇, 𝑡𝑖𝑚𝑒 𝑏𝑖𝑛, 𝐹, 𝑖𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 𝑐𝑎𝑙. 𝑓𝑎𝑐𝑡𝑜𝑟
[𝑃ℎ
𝑚2𝑛𝑚 𝑠 𝑠𝑟]
FIDA measurement
0 m2/s 0.3 m2/s
0.5 m2/s 1 m2/s
0 m2/s 0.3 m2/s
0.5 m2/s 1 m2/s
Zeff = 2 Zeff = 3 Zeff = 4
NBI 1
NBI 2
FIDA01
FIDA02
IP and BT
Non-charge exchange component (OV, CII, OIV..) can be subtracted by beam modulations.
Weight function depends on,
Minimum energy and Gyro-angle weight [1]𝑬 = 𝑬𝝀 𝟏 − 𝒑𝟐 𝑬 =𝑬𝝀
𝝀||𝒑 + 𝝀⊥ 𝟏 − 𝒑𝟐𝟐
[1] Luo Y, Heidbrink W W, Burrell K H, Kaplan D H and Gohil P 2007 Rev. Sci. Instrum. 78 033505
[2] W. Heidbrink, D Liu, Y. Luo, E. Ruskov, and B. Geiger.Commun. Comput. Phys., 10(10):716–741, 2011.
[3] O. Meneghini et al., Nucl. Fusion 55, 083008 (2015).
[4] W W Heidbrink et al., PPCF 49 1457-1475 (2007)
[5] Luo, PhD thesis (2007)
Geometric weighting
18602 at 13.65 s
R, Z = 190 m, -0 m
BEAM A, B, C (100, 70, 70 keV)
Fast ion distribution function calculated by NUBEAM
convolutions
a=0.065pi
a=0.2pi
vertical
tangential
a, angle between b⊥1 and LOS at b∥, b⊥1 plane
Examples of weighting function for KSTAR
𝑺 = න𝒘 𝑬, 𝒑 ⅆ𝑬ⅆ𝒑
FIDASIM [2] calculations
Modelling setup
FIDASIM with PresetModels beam and halo
neutrals, calculates VBE, cx probabilities, weight function,
active FIDA radiance using sightline geometry
PresetNeutral beam geometry
EquilibriumPlasma profiles
TRANSP or NUBEAM (OMFIT [3])Theoretical fast ion distribution
functionsF (E, p)
FIDA and NPA
2019 FIDA01 geo, equilibrium with CCW BT and IP (21747Z35)
Comparison with
the measurements (MSE LOS)
Spectra measured by MES LOS
w/o modulation @ 2.00-2.35 s
FIDASIM
with neutral beam current fraction
(0.467, 0.374, 0.159) ↓
BES
CII
CII
BES
CH01 R = 1748 mm
CH20 R = 2175 mm
FIDA01
FIDA02
MSE CH16 ~ CH01
CH01 ~ CH10CH01 CH20
Geometrical inputs for FIDASIM →
Comparison with physical parametersSensitivity study with Zeff and Df
FIDA spectrometer Calibration of each line of sight
Wavelength calibrations
Predictions of E-p space sensitivity (weight function)
Co
un
t[a
. u
.]
-0.0162x+667.5170
-0.0162x+667.5113
-0.0162x+667.5139
-0.0162x+667.4823
-0.0162x+667.4634
-0.0162x+667.4182
-0.0162x+667.3651
-0.0162x+667.3206
Target wavelength
Ne (653.29 nm)
Hα (656.27 nm)
Dα (656.09 nm)
Ne (659.89 nm)
Ra
dia
nce
[P
h/(
m2
*n
m*
s*sr
]
Application for each CH.
For the sensitivity study, effective Z, profile shape of Zeff, fast ion diffusivity and current fraction are scanned. Especially large values of Zeff enhances bremsstrahlung emissions
signal to noise ratio is gone bad. Bremsstrahlung, one order larger than FIDA intensity (∝ ne2)
Since KSTAR FIDA systems in mid-plane and tangential array (a ~ 0.5 pi)
Convolution shows the narrower region of the E-p coverage.
Patch panel
FIDA (fast ion Dα) system consists of two mid-plane tangential arrays.
J-port cassette: Integrated Optics module shared with visible spectroscopy and filter scope
Integrated FIDASIM modelling platform (handling the profile data + TRANSP outputs) is necessary.
ⓐ ⓑ
ⓒ
ⓐ FIDASIM run
ⓑ FIDASIM calculation results with FIDA01It shows blue shifted BES and is compared with FIDA measurements but
it is hardly matched in one time calculation. Need iterations
ⓒ comparison with MSE measurement and the calculationscalculation is qualitatively matched with MSE measurement. Since MSE
and FIDA view aligned looking at beam line in opposite side, this can be
good base material for reliability check.
ⓓ neutral density calculations with beam grid (FIDASIM inputs) at
FIDA focal points
ⓔ neutral density of each component along the beam lines (Xbeam)
ⓕ neutral density at FIDA LOSs
ⓕ
Neutral density at focal points of FIDA
FIDA01 FIDA02
ⓓ
ⓔ
FIDA01 FIDA02
1. Spectroscopic measurements in beam into gas and plasma discharges will be performed for the reference spectra.
2. Additional FIDA array (FIDA02) will be introduced in 2019 campaign to span the detectable fast-ion phase-space.
3. FIDASIM iteration is necessary with newly acquitted data.
4. To expand FIDA operational range of fast-ion phase-space, optical alignment is under discussion.
5. To understand fast ion physics, various operation scenarios and relevant MHD instabilities will be investigated.
Summary
FIDA density with heating in time trace [4]
Scaling study with FIDA density [5]
FIDA density = FIDA intensity/beam neutral density
∝ Fast ion density (∝ Pinjf(Te)/ne) ∝ Fast ion pressure
FIDA density profile seems to be qualitatively and quantitatively
matched with shape of fast ion pressure (TRANSP)Single energy FIDA profiles
661 nm ~70 keV Pf profile comparison in DIII-D [3]
661 nm ~ 653 nm
Fast ion pressure calculated by TRANSP FIDA density
21747Z35
References
AcknowledgmentsThe authors would like to acknowledge the KSTAR team and appreciate Alvin Garcia for useful comments.
