05aE15P
ヘリオトロンJにおける電子バーンスタイン放射計測システムの開発
Development of Electron Bernstein Emission Diagnostic System on Heliotron J
長﨑百伸1, F. Volpe2, 中村祐司3, 上岡壮平3, 藤田直己3, 坂本欣三1, 水内亨1, 岡田浩之1,南貴司1, 門信一郎1, 小林進二1, 山本聡1, 大島慎介1, 史楠1, 木島滋1, L. Zang3, 釼持尚輝3,伊神弘恵4, 吉村泰夫4, N. Marushchenko5, 佐野史道1
K. Nagasaki, F. Volpe, Y. Nakamura, S. Kamioka, N. Fujita, K. Sakamoto, et al.
京大エネ理工研1, コロンビア大2, 京大エネ科3, 核融合研4, IPP, Greifswald5
IAE, Kyoto Univ.1, Columbia Univ.2, GSES, Kyoto Univ.3, NIFS4, IPP, Greifswald5
19-6

Standard Configuration,B=1.22T, n e(0)=2x10 m-3

0.000
0.1000

Poloidal Injection Angle (deg)0.2000Vacuum chamber
port boundary-80.30000.40000.50000.60000.70000.80000.9000-10

1.000-12-14-16-14-12-10-8-6

Toroidal Injection Angle (deg)Fig. 1. O-X mode conversion window for thefrequency of 35GHz in Heliotron J
1.0
ne/ne=1%

0.8
Transmission efficiency

Use of electron Bernstein Waves (EBWs) is
attractive for heating/current drive, electron
temperature diagnostic [1] and magnetic pitch angle
profile measurement [2] at high densities notaccessible to electron cyclotron waves. The EBWs
have advantage of no density limit and high optical
thickness even at low Te. Electron Bernsteinemission (EBE) has been studied for Te
measurement at high density regime in Heliotron J.
Figure 1 shows a calculation result on O-X mode
conversion efficiency using the TRAVIS code. The
existing EC launcher antenna has an access window
for the O-X conversion for 35 GHz frequency with5 deg and 3 deg wide in the toroidal and poloidaldirections, respectively. The density fluctuation
may affect the O-X mode conversion efficiency, as
shown in Fig. 2. The transmission efficiency isreduced even at optimum angle with an increase indensity fluctuation amplitude, suggesting thathigh-density improved modes are preferable for theEBE diagnostic. A ray tracing code, KRAY, hasbeen developed to calculate heating and emission
profiles via O-X-B process, which solves theradiative transfer equations [3] in the 3-D magnetic
field structure. The calculation shows that thepower can be deposited at the core region [4].
A multi-channel radiometer system is being
assembled and tested for the EBE measurement.
Since the electron density in NBI plasmas is
typically ne<41019 m-3, the frequency of Ka-band(26-40 GHz) is chosen to measure the radiationfrom core. As the radiometer is connected to thetransmission line and steerable antenna of theexisting ECH/ECCD system, it will be possible toperform angular scans of conversion efficiency that
can also provide guidance to EBW heating andcurrent drive. The designed EBE measurement
system consists of a Gaussian optics antenna, auniversal polarizer and a radiometer. Preliminary
tests showed that the radiometer detected 35 GHz
microwaves of 0.2 nW level intensity.

f =35GHz
B=1.25Ty=2cmne/ne=2%

Ln=2cmne/ne=4%0.6

ne/ne=8%0.4

ne/ne=16%

0.2

0.0
30

35

40

45

50

5560

 (deg)Fig. 2. Effect of density fluctuation ontransmission efficiency.  is the angle between
the wave vector and the magnetic field.
References[1] F. Volpe, H. P. Laqua and the W7-AS Team,
Rev. Sci. Instrum. 74, 1409 (2003).
[2] F. Volpe, Rev. Sci. Instrum. 81, 10D905(2010).
[3] K. Nagasaki, et al., Plasma Phys. Control.
Fusion 44 409 (2002).
[4] S. Kamioka, et al., this conference.