Page 5 - Thomson scattering systems on C-2W field-reversed configuration plasma experiment

10C118-5 Zhai et al.
Rev. Sci. Instrum. 89, 10C118 (2018)
in which λs-center is the center wavelength of an individual polychromator channel. The corresponding equivalent plasma radiation in the AC channel before subtraction is
SAC−plasma = (RAC ∗ hc ∗ Ne−photon−plasma)/QAPD. (8) λs−center
The variance of the plasma radiation in the AC channel is therefore
system has been installed and commissioned, which is now routinely operational on a daily basis to provide Te and ne profile measurements at 16 radial locations with up to 35 temporal snapshots at up to 20 kHz with the burst mode of laser operation. Te and ne profile data are processed with the maximum likelihood method and available after each shot. Jet TS system construction is under way, which will cover Te and ne profiles at 5 radial locations with 100 Hz temporal resolution.
ACKNOWLEDGMENTS
We thank our shareholders for their support and trust, and all fellow TAE staff for their dedication, excellent work, and extra efforts.
1T. N. Carlstrom, J. C. DeBoo, R. Evanko, C. M. Greenfield, C. L. Hsieh, R. T. Snider, and P. Trost, Rev. Sci. Instrum. 61, 2858 (1990).
2K. Zhai, T. Schindler, J. Kinley, B. Deng, and M. C. Thompson, Rev. Sci. Instrum. 87, 11D602 (2016).
3E. Pasch, M. N. A. Beurskens, S. A. Bozhenkov, G. Fuchert, J. Knauer, R. C. Wolf, and W7-X Team, Rev. Sci. Instrum. 87, 11E729 (2016).
4S. Kajita, T. Hatae, H. Tojo, A. Enokuchi, T. Hamano, K. Shimizu, and H. Kawashima, Rev. Sci. Instrum. 86, 083511 (2015).
5C. J. Barth, H. J. v. d. Meiden, T. Oyevaar, and N. J. Lopes Cardozo, Rev. Sci. Instrum. 72, 1138 (2001).
6K. Narihara, I. Yamada, H. Hayashi, and K. Yamauchi, Rev. Sci. Instrum. 72, 1122 (2001).
7R. Scannell, M. J. Walsh, P. G. Carolan, A. C. Darke, M. R. Dunstan, R. B. Huxford, G. McArdle, D. Morgan, G. Naylor, T. O’Gorman, S. Shibaev, N. Barratt, K. J. Gibson, G. J. Tallents, and H. R. Wilsonless, Rev. Sci. Instrum. 79(10), 10E730 (2008).
8B. P. LeBlanc, R. E. Bell, D. W. Johnson, D. E. Hoffman, D. C. Long, and R. W. Palladino, Rev. Sci. Instrum. 74, 1659 (2003).
9A. Diallo, B. P. LeBlanc, G. Labik, and D. Stevens, Rev. Sci. Instrum. 83, 10D532 (2012).
10D. J. Den Hartog, J. R. Ambuel, M. T. Borchardt, A. F. Falkowski, W. S. Harris, D. J. Holly, E. Parke, J. A. Reusch, P. E. Robl, H. D. Stephens, and Y. M. Yang, Rev. Sci. Instrum. 81, 10D513 (2010).
11 J. A. Reusch, M. T. Borchardt, D. J. Den Hartog, A. F. Falkowski, D. J. Holly, R. O’Connell, and H. D. Stephens, Rev. Sci. Instrum. 79, 10E733 (2008).
12K. Zhai, F. S. B. Anderson, K. Willis, K. Likin, and D. T. Anderson, Rev. Sci. Instrum. 75, 3900 (2004).
13J. Sheffield, Plasma Phys. 14, 783 (1972).
14M. W. Binderbauer et al., AIP Conf. Proc. 1721, 030003 (2016).
15A. Ottaviano, T. M. Schindler, K. Zhai, E. Parke, E. Granstedt, and
M. C. Thompson, “Characterization and calibration of the Thomson scatter- ing diagnostic suite for the C-2W field-reversed configuration experiment,” Rev. Sci. Instrum. (these proceedings).
16D. M. Ponce-Marquez, B. D. Bray, T. M. Deterly, C. Liu, and D. Eldon, Rev. Sci. Instrum. 81, 10D525 (2010).
􏰀RAC ∗ λ V =􏰄
hc 2 􏰁
s−center 􏰅 􏰅􏰅
N e−photon−plasma
∗ Tgate ∗ SDC.
plasma 􏰄􏰄
􏰄 Qapd 􏰅
=
􏰂􏰃
(RAC)2 ∗ hc λs−center
RDC ∗ Qapd
(9)
For a test Te and ne, the signal level and their variance
in each polychromator wavelength channel can be calculated
with Eqs. (3) and (5). If the experimental signal is S exp for ts
polychromator channel ch, the likelihood of such a test Te and ne to actual Te and ne is
exp 2 (Sts −Sts )
1
Lch = 1
e 2∗VarianceAC .
Combining all the polychromator channels, the overall
(2π ∗ VarianceAC ) 2
likelihood of the test T and n to be the actual T and n
error bars can be obtained when Ltotal is reduced by e1/2 which is 1-σ point. Figure 5 shows an example of the data processing procedure.
It is apparent from Eq. (1) that ne is a scale factor, so the
processing of Te and ne can be separated. For a fixed test ne,
normalized S to 􏰈 S / 􏰈 SEXP in which summation over TS chts chts
polychromator channels becomes only Te dependent. Once
T is determined from this procedure, n can be obtained in a ee
similar way. This reduces the procedure of 2-D optimization to two 1-D optimization procedures and improves the efficiency of post-shot data processing.
IV. SUMMARY
A suite of Thomson scattering systems has been designed and constructed on C-2W experiments. The central TS
ee ee Ltotal = 􏰊 Lch.
is (11)
ch
Te and ne can be obtained when maximizing Ltotal , and the
(10)