Imaging x-ray crystal spectrometer on EAST

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Neutron diagnostics, including flux and energy spectrum measurements, have been applied on the experimental advanced superconducting tokamak (EAST). The absolute calibration of neutron yields has been achieved by a calculation method using the Monte Carlo automatic modeling (MCAM) system and the Monte Carlo N-Particles (MCNP) code. Since the neutron yield is closely related with the ion density and temperature, it is a good measure of plasma performance, especially the wave heating effect. In ion cyclotron range of frequencies (ICRF) experiments, the increase in the ion temperature derived by the neutron yield indicates an effective plasma heating. Minority protons damp a large fraction of the total wave power, and then transfer part of the energy to deuterium by collisions. Neutron spectrum measurements also indicate that no tail is created by high energy deuterons during ICRF heating. However, the ion temperature derived by the neutron yield is consistent with the result by using a poloidal X-ray imaging crystal spectrometer (PXCS), showing a reliable transport calculation.

Section: Introductionsupporting

confidence: 83%

Neutron Yields Based on Transport Calculation in EAST ICRF Minority Heating Plasmas

Li¹,

Wan²,

Guo³

et al. 2013

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“…Z eff is from the visible bremsstrahlung [34]. T i comes from the charge exchange recombination spectroscopy [35,36] and the x-ray imaging crystal spectrometer [37,38] data at the central region and match T T i e = in the edge region. During this scenario, the fast-ion D-alpha diagnostic is still under development on EAST, so direct measurement of the contribution of fast particles is unavailable.…”

Section: Experimental Setup and Modelingmentioning

confidence: 99%

Kinetic equilibrium reconstruction for the NBI- and ICRH-heated H-mode plasma on EAST tokamak

Zheng¹,

Xiang²,

CHEN³

et al. 2018

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The equilibrium reconstruction is important to study the tokamak plasma physical processes. To analyze the contribution of fast ions to the equilibrium, the kinetic equilibria at two time-slices in a typical H-mode discharge with different auxiliary heatings are reconstructed by using magnetic diagnostics, kinetic diagnostics and TRANSP code. It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core plasma due to the neutral beam injection power is primarily deposited in the core region. The fast-ion current contributes mainly in the core region while contributes little to the pedestal current. A steep pressure gradient in the pedestal is observed which gives rise to a strong edge current. It is proved that the fast ion effects cannot be ignored and should be considered in the future study of EAST.

“…2) with B t = 1.9 T, I p = 400 kA, n e < 4 × 10 19 m −3 was heated by ∼1.3 MW lower hybrid wave (LHW) and ∼0.9 MW wave in ion cyclotron range of frequency (ICRF). The electron density and temperature were measured by Thomson scattering diagnostics [21] and the T i profile was taken from X-ray imaging crystal spectrometer (XCS) [22] . The T e profile is fitted with a tension spline function [23] .…”

Section: Current Calculations For Long Pulse H-mode Plasmas Using Rf mentioning

confidence: 99%

Long Pulse H-Mode Scenarios Sustained by RF Heating on EAST

Gao

Zhang

et al. 2015

EAST has demonstrated its capability of long pulse operation using RF heating (LHCD and ICRF) in past experiments. One key issue to realize the long pulse H-mode experiments is to sustain the plasma current for steady state operation. Based on the calculations of the transport code ONETWO and its coupled RF code GENRAY, two scenarios have been proposed to achieve the 10 s H-mode plasma with Ip=400 kA, < ne >=4.5×10 19 m −3 , βN=2, and the 100 s H-mode plasma with Ip=280 kA, < ne >=3.5×10 19 m −3 , βN =1.8 recently. The current drive of lower hybrid wave is an important issue in the two scenarios. An experimental result on lower hybrid current drive in H-mode plasmas on EAST is also presented.