Direct Observation of Runaway Electron Beams in EAST Yuejiang Shi Baonian Wan, Jia Fu, Huixian Gao,...
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Transcript of Direct Observation of Runaway Electron Beams in EAST Yuejiang Shi Baonian Wan, Jia Fu, Huixian Gao,...
Direct Observation of Runaway
Electron Beams in EAST
Yuejiang Shi
Baonian Wan, Jia Fu, Huixian Gao, Fudi Wang, Jiahong Li, and EAST team
Institute of Plasma Physics, Chinese Academy of Sciences,China
ASIPP
4th US-PRCMagnetic Fusion Collaboration Workshop
5-6 May 2008, Austin, Texas, USA
EAST
Self-Introduction
I am the leader of the advanced spectroscopy diagnostic group for HT-
7 and EAST. This group includes charge exchange recombination
spectroscopy (collaboration with FRC_UT),UV-VIS OMA Spectrometer
for impurity measurement, and X-ray Imaging Crystal Spectrometer
(collaboration with PPPL and KSTAR). Main interesting are LHCD
physics, the thermal transport of plasma, the impurity transport in
plasma.
EAST
Outline I. Synchrotron radiation of the
runaway electrons in tokamaks
II. Experimental setup
III. Experimental results
IV. Summary
EAST
Synchrotron radiation spectra of the runaway electrons
The spectra of runaways with different energy
EAST
I. Synchrotron radiation of the runaway electrons in tokamaks
The spectra of runaways with different pitch angle
The profiles of radiation power measured with XUV array
The radiation patterns with different q and fixed pitch angle(p = 0).
EAST
I. Synchrotron radiation of the runaway electrons in tokamaks
Numerical simulated synchrotron patterns of the runaway beams
The radiation pattern with p = 0.06. A parabolic-like q profile is assumed
Two color (RGB) cameras
Wavelength range:380nm-750nm
Sampling frequency:75fps
Pixel number:640480
Appointed purpose in EAST:
Monitor discharge status and plasma shape
EAST
II. Experimental setup
Video of the camera
The relation between the runaway energy and the ratios of the three color pixels. The shading bar are corresponded to the experimental data. Simulation of test particle dynamic equation:,……Elim=47~49MeV, p =0.06~0.07 for Te=0.5keV
Elim=21~432MeV, p =0.1~0.13 for Te=0.7keV …………………….
EASTIII. Experimental results(1)
Typical image in a circular-configuration shot
Waveforms of the discharge in EAST
From this image,
p and q(0) are estimated as 0.06 and
2.8, respectively
EASTIII. Experimental results(2)
The shell pattern of synchrotron radiation in EAST
The shell is located around q=1 surface
The shell is asymmetry in HFS and LFS
IV. Summary It is the first time to observe the synchrotron
radiation emitted from runaway electrons with a common visible camera in EAST tokomak. Very clear synchrotron radiation images from runaway electron beams have been obtained in EAST tokamak. Both the pitch angle and energy limit runaway electrons have been self-consistent derived from the measurement of synchrotron radiation. The experimental results are partly consistent with the test particle dynamics numerical simulation. A strange stable shell shape of synchrotron radiation can be observed. The mechanism for the formation of this shell is unclear.
EAST