A new soft x-ray pulse height analysis array in the HL-2A tokamak

Zhang, Y. P.; Liu, Yi; Yang, Jianhua; Song, X. Y.; Liao, Min; Li, X.; Yuan, Guoliang; Yang, Qingwei; Duan, Xuru; Pan, C.H.

doi:10.1063/1.3263910

Cited by 10 publications

(6 citation statements)

References 10 publications

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“…17416, the energy of ECW was deposited in the core of plasma because the ECRH was near-axis heating. 20 In this scenario, the T e profile was evidently peaked during ECRH, as shown in Fig. 9(a).…”

Section: Theoretical Calculations and Discussionmentioning

confidence: 84%

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory

Zhang¹,

Isobe

Liu³

et al. 2012

Physics of Plasmas

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Physics related to fast ions in magnetically confined fusion plasmas is a very important issue, since these particles will play an important role in future burning plasmas. Indeed, they will act as primary heating source and will sustain the self-ignited condition. To measure the fast ion slowingdown times in a magnetohydrodynamic-quiescent plasmas in different scenarios, very short pulses of a deuterium neutral beam, so-called "blip," with duration of about 5 ms were tangentially coinjected into a deuterium plasmas at the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak [L. W. Yan, Nucl. Fusion 51, 094016 (2011)]. The decay rate of 2.45 MeV D-D fusion neutrons produced by beam-plasma reactions following neutral beam termination was measured by means of a 235 U fission chamber. Experimental results were compared with those predicted by a classical slowing-down model. These results show that the fast ions are well confined with a peaked profile and the ions are slowed down classically without significant loss in the HL-2A tokamak. Moreover, it has been observed that during electron cyclotron resonance heating the fast ions have a longer slowing-down time and the neutron emission rate decay time becomes longer. V C 2012 American Institute of Physics. [http://dx.

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Section: Theoretical Calculations and Discussionmentioning

confidence: 84%

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory

Zhang¹,

Isobe

Liu³

et al. 2012

Physics of Plasmas

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“…In order to measure the ion energies associated with the collisions, the target was moved from the small chamber to the middle of the second or third viewing window and the small chamber was removed. Figure 14 shows the energy spectrum of x-rays measured using the silicon drift detector [26] shown in figure 1. The spectrum in figure 14 is a single Maxwellian distribution with a particle energy of 2.0 keV, obtained by statistical analysis of the energy spectrum.…”

Section: Particle Velocity and Ion Energymentioning

confidence: 99%

Enhanced density in a stabilized high-current plasma beam

Zheng

Gou

Zhang

et al. 2021

Plasma Phys. Control. Fusion

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Externally generated, axial magnetic fields used to confine high-current plasma beams in compact linear devices are usually 0.5 Tesla or less and can be insufficient to suppress plasma instabilities. Such an issue is addressed in this study by closely winding the current-carrying cable around a small chamber attached to the end of a linear device. The magnetic field generated inside the small chamber during the high-current pulse reached 0.8 Tesla at the peak current of 10.83 kA. Formation of a steady plasma beam through a mixture of argon, hydrogen and helium was photographed by a high-speed camera at the instant of the peak current. The beam width profile starts from over 24.8 mm at the upstream location and becomes thinner with distance down-stream. At the location of laser-interferometer measurement, at the right-most viewing window on the test chamber, the beam width was estimated as 7.4 mm and plasma density was evaluated to be 1.0 × 1022 m−3, an increase of two orders of magnitude compared to a previous study. A simple relationship was derived for the plasma density as a function of beam width. Based on examination of the metal target at the far end, the final beam width was estimated as 50 µm, with the plasma density evaluated to be 4.31 × 1022 m−3, with a calculated ion energy of 4.35 keV, consistent with x-ray spectrum measurements.

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“…MR is also prevalent in laboratory experiments, [8][9][10][11][12][13][14][15] particularly in tokamaks where electron energization is commonly observed during the internal kink mode sawtooth cycle. X-ray detectors have become increasingly useful diagnostics for diagnosing electron dynamics in high temperature plasma [16][17][18][19][20][21][22][23] experiments. Parallel and anti-parallel anisotropy in x-ray emission from non-thermal electrons, attributed to runaway acceleration driven by the inductive electric field created during the impulsive sawtooth crash, has been measured in the T- 10 18 , VTF, 8 TCV, 9 and PLT 11 tokamaks.…”

Section: Introductionmentioning

confidence: 99%

Turbulence-driven anisotropic electron tail generation during magnetic reconnection

et al. 2018

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Magnetic reconnection (MR) plays an important role in particle transport, energization, and acceleration in space, astrophysical, and laboratory plasmas. In the Madison Symmetric Torus reversed field pinch, discrete MR events release large amounts of energy from the equilibrium magnetic field, a fraction of which is transferred to electrons and ions. Previous experiments revealed an anisotropic electron tail that favors the perpendicular direction and is symmetric in the parallel. New profile measurements of x-ray emission show that the tail distribution is localized near the magnetic axis, consistent modeling of the bremsstrahlung emission. The tail appears first near the magnetic axis and then spreads radially, and the dynamics in the anisotropy and diffusion are discussed. The data presented imply that the electron tail formation likely results from a turbulent wave-particle interaction and provides evidence that high energy electrons are escaping the core-localized region through pitch angle scattering into the parallel direction, followed by stochastic parallel transport to the plasma edge. New measurements also show a strong correlation between high energy x-ray measurements and tearing mode dynamics, suggesting that the coupling between core and edge tearing modes is essential for energetic electron tail formation.

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A new soft x-ray pulse height analysis array in the HL-2A tokamak

Cited by 10 publications

References 10 publications

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory

Enhanced density in a stabilized high-current plasma beam

Turbulence-driven anisotropic electron tail generation during magnetic reconnection

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