30D21P

直線プラズマ装置PANTAにおける分光計測とアーベル変換による画像再構成
Reconstruction of radial profiles of light emission intensity in PANTA

柿川 伸介1, 藤澤 彰英2,3, 永島 芳彦2,3, 大坪 聡1, 稲垣 滋2,3, 小林 達哉1, 山下 哲生1, 山田 宗太郎1,藤野博充1, 大野翔1, 糟谷 直宏2,3, 佐々木真2,3, 伊藤早苗2,3, 伊藤公孝3,4

Shinsuke Kakigawa1, Akihide Fujisawa2,3, Yoshihiko Nagashima2,3
Satoru Ohtsubo , Shigeru Inagaki2,3 Tatsuya Kobayashi1, Tetsuo Yamashita1, Soutaro Yamada1, HiromitsuFujino1, Syou Ohno1, Naohiro Kasuya2,3, Makoto Sasaki2,3, Sanae –I. Itoh2,3, and Kimitaka Itoh3,4
1

1

九州大学総合理工学府,2九州大学応用力学研究所,3伊藤極限プラズマ研究連携センター,4核融合科学研究所
1Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
2
Research Institute for Applied Mechanics, Kyushu University,
3Itoh Research Center for Plasma Turbulence, Kyushu University,
4
National Institute for Fusion Science

integrated profile. Figure 1 shows an example ofthe measured line-integrated profile and thelocal emission profiles inferred from the methodof solving the matrix equation and applied Abelinversion with spline interpolation in the case ofthe blue light (ArII emission) for an argon
plasma, suggesting a sharply peaked profilearound the plasma center of r<~2cm. The
evaluation of these reconstructed radial profile
will be discussed.
The poster presents the initial results obtainedwith the developing system for tomography anddetails of the reconstruction methods, with theprogress and future in the construction of a
two-dimensional observation system in PANTA.
(a)Ar plasma(b)AfterAbelsolving thematrixinversion

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A.U.
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Understanding of plasma turbulence is an
essential issue to realize and control fusionplasmas since turbulence-driven transport
affects significantly plasma confinement.
Turbulence
state
consistsofvarious
spatio-temporal scale fluctuations, therefore,
the plasma turbulence needs to be observed
multi-dimensionally with covering a wide rangeof spatial scales. In a cylindrical plasma device
PANTA
in
KyushuUniversity[1],aspectroscopic system surrounding the plasma
for tomography is being constructed to measure
two-dimensional structure of turbulence with afine resolution, and as its first trial,
thereconstruction of local emission profile in steadystates is being made from one dimensional
measurement in argon plasmas of PANTA.
PANTA produces a linear cylindrical plasma
with the diameter of ~0.1 m and axial length of 4
m by helicon wave (7 MHz, 3 KW).
The
line-integrated measurements were carried out
for four different ranges of wavelength by opticalfilters; blue (480 nm), red (700 nm), infrared (900nm), and UV (300 nm) light. The system for eachwavelength range consists of 33 channels alignedin the vertical direction. In this experiment, themagnetic field was fixed at 0.9 kG with argon gaspressure of 1 mTorr. The measurement wasperformed with selecting 16 channels thatcovered the plasma region from the center to anedge on one side.
Assuming azimuthal symmetry of thecylindrical plasmas, radial profile of local
emission is reconstructed by different procedures,i.e., using the Abel inversion after fitting
functions to the measured profile of line
integrated profile, and solving a linear matrix
equation to connect the local emission to the line

020 40 60 80r(mm)with spline function
solving the matrix
with spline function

0 20 40 60 80r(mm)0 20 40 60r(mm)80Fig. 1 (a) Measured profile of light intensity withblue in an argon plasma, and (b) an inverted radial
profile of the light emission.

This work is partly supposed by agrant-in-aid for scientific research from JSPS
(23246162, 21224014, 23360409, 23360414)
References[1] H Arakawa et al Plasma Phys. Control. Fusion
53 115009(2011)