05aE28P
GAMMA 10におけるThomson散乱計測システムの進展
Progress of the Thomson scattering system in GAMMA 10
吉川正志1、長洲和英1、島村侑希1、安原亮2、嶋頼子1、小波蔵純子1、北川和1、森下雅央1、坂本瑞樹1、河原崎遼1、南龍太郎1、中嶋洋輔1、今井剛1、山田一博2、舟場久芳2、南貴司3、市村真1
1
YOSHIKAWA Masayuki , NAGASU Kazuhide1, SHIMAMURA Yuuki1, YASUHARA Ryo2,SHIMA Yoriko1, et al.
1

筑波大プラ研セ、2 核融合研、3 京大エネ理工
1
PRC, Univ. Tsukuba, 2NIFS, 3AE, Kyoto Univ.

Thomson scattering (TS) measurement is one of
the most reliable diagnostic to measure the electron
temperature and density in plasmas. In GAMMA 10,
the yttrium-aluminium-garnet (YAG)-TS system
has been constructed with the large solid angle of
TS collection optical system. In the former
experiments, we could measure the electron
temperature and density at only one radial position
in a single plasma and laser shot. We added theobserving channels with adding the optical fibers,
polychromators and oscilloscopes. We successfully
obtained the multi-positions radial electron
temperatures and densities in a single plasma andlaser shot. We had successfully constructeddouble-pass TS system of a polarization based
system with image relaying optics and had thedoubly increased TS signals. In order to increase TS
signals more, we are developing the multi-pass TS
method of a polarization based system. This scheme
can be implemented by modifying a basic
single-pass TS system with the addition ofpolarization devices, a high-reflection mirror, andlenses for the image relaying of the laser beam. We
successfully constructed the multi-pass TS system.
GAMMA 10 is an effectively axisymmetrized
minimum-B anchored tandem mirror with barrier
and plug at both end-mirrors. In GAMMA 10, thetypical electron density, electron and ion
temperatures are about 2  1012 cm-3, 0.1 keV and 5keV, respectively. The YAG-TS system isconstructed with the laser, the incident optics, thelight collection optics, the signal detection
electronics, and the data recording system. A 10 Hz
Nd:YAG laser (Continuum, Powerlite 9010) with anenergy per pulse of 2 J and a pulse width of about
10 ns, operating at the fundamental wavelength of1064 nm is used. The laser beam is injected to theplasma from the down side port though the afocusing lens of f = 2 m. The laser beam diameter at
the plasma center is about 1 mm. For the lightcollection optics, we used the spherical mirror withAl:SiO2 coated, curvature radius of 1.2 m anddiameter of 0.6 m. The scattered light is collectedby the spherical mirror, reflected and reaches abundled optical fiber with cross-section of 2×7 mm.
The magnification of the collection optics is 2.2.
The length of scattering volume along the laser is15.4 mm and scattering angle is 90◦. A solid angle of0.078 sr can be realized of the light collectionoptics. After passing through the plasma, the laser
beam is ejected from the upper side port andabsorbed by the beam dump. The 6.67 m long
bundled optical fiber (Mitsubishi Densen,FS10-43001A) is connected to the 5 channel
polychromator. The bundled optical fiber has 5channels and each channel is constructed by 48
fibers with the core diameter of 400 m and thevery large numerical aperture of about 0.47. The 5channel polychromator (TS139) is on loan from thenational institute for fusion science (NIFS). We
constructed new two polychromators (TS056 andTS149) with new Si-APDs (PerkinElmer,C30659-1060-3AH)
withpreamplifier.
Four-channel high speed oscilloscopes (Tektoronix,DPO4034B, and two IWATSU, DS5524) were usedtomeasurefourwavelengthchannels
simultaneously with bandwidth of 350 MHz and200 MHz, and sampling rate of 2.5 GS/s and 1 GS/s,
respectively.
We apply the YAG-TS system to measureelectron temperature and density in the GAMMA
10 plasma. The radial electron temperature anddensity profiles are successfully obtained.
Moreover, we show the newly constructed
multi-pass TS system that uses polarization optics,
and we demonstrate the results of the multi-pass TS
system installed in GAMMA 10 with Rayleigh andRaman scattering experiments.