Tomographic Reconstruction of Imaging Diagnostics with a Generative Adversarial Network

Kinoshita, Naoki; Nishiura, M.; Nakamura, Kimie; Yoshida, Zensho

doi:10.1585/pfr.14.1202117

Cited by 4 publications

(6 citation statements)

References 8 publications

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“…A tomographic reconstruction method using a deep learning technique has been developed to obtain local-intensity profiles from imaging-diagnostic data [10]. The pairs of local emissivity and line-integrated images which simulate an experimental system are prepared to train a network using the model function for plasma profile developed in previous studies of the RT-1 [9,11].…”

Section: Formation Of Self-organized Plasmasmentioning

confidence: 99%

Inward diffusion driven by low frequency fluctuations in self-organizing magnetospheric plasma

Kinoshita¹,

Yokota²,

Nishiura³

et al. 2022

Nucl. Fusion

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The new findings for dynamic process of inward diffusion in the magnetospheric plasma are reported on the RT-1 experiment: (i) The evolution of local density profile in the self-organized process has been analysed by the newly developed tomographic reconstruction applying a deep learning method. (ii) The impact of neutral-gas injection excites low-frequency fluctuations, which continues until the peaked density profile recovers. The fluctuations have magnetic components (suggesting the high-beta effect) which have two different frequencies and propagation directions. The phase velocities are of the order of magnetization drifts, and both the velocities and the intensities increase in proportion to the electron density. The self-regulating mechanism of density profile works most apparently in the naturally made confinement system, magnetosphere, which teaches the basic physics of long-lived structures underlying every stationary confinement scheme.

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Section: Formation Of Self-organized Plasmasmentioning

confidence: 99%

Inward diffusion driven by low frequency fluctuations in self-organizing magnetospheric plasma

Kinoshita¹,

Yokota²,

Nishiura³

et al. 2022

Nucl. Fusion

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“…Particles in the low energy set have been extensively studied with the guiding center approximation 13 . Particles in the high energy sets should also be detectable in physical systems 12,16 .…”

Section: Discussionmentioning

confidence: 99%

“…Motions of a charged particle in a dipole magnetic field were first systematically investigated by Störmer 8 . Due to the axis symmetry of the system, it can be reduced to a 2D Hamiltonian system and is later called the Störmer problem for its broad implications in mathematics, space science, and physics 1,[9][10][11][12] . To better understand the Van Allen radiation belt discovered in the mid-20th century, there have been rea) Also at Phillips Academy Andover, 180 Main Street, Andover, MA, 01810, USA b) Electronic mail: liusm@pmo.ac.cn newed interests in solving the Störmer's problem.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, periodic orbits in the equatorial plane have been explored extensively 7 , and there are also a few branches of periodic orbits in the Meridian plane at relatively high energies with distinct orbital shapes [3][4][5] . At low energies, due to the presence of approximate adiabatic invariant, the problem can be further simplified 13,14 , and the results, the so-called guiding center approximation, have been applied to studies of pulsars, radiation belts, and dynamics of particles in magnetic confinement devices 12,15,16 .…”

Section: Introductionmentioning

confidence: 99%

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From period to quasiperiod to chaos: A continuous spectrum of orbits of charged particles trapped in a dipole magnetic field

Xie

Liu

2020

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Via evaluation of the Lyapunov exponent, we report the discovery of three prominent sets of phase space regimes of quasi-periodic orbits of charged particles trapped in a dipole magnetic field. Besides the low energy regime that has been studied extensively and covers more than ∼ 10% in each dimension of the phase space of trapped orbits, there are two sets of high energy regimes, the largest of which covers more than ∼ 4% in each dimension of the phase space of trapped orbits. Particles in these high energy orbits may be observed in space and be realized in plasma experiments on the Earth.

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“…been demonstrated in solving the coherence imaging spectroscopy (CIS) [14]. The CIS measured the projection quantity onto the line of sight.…”

Section: Jinst 15 C01002mentioning

confidence: 99%

Collective Thomson scattering with 77, 154, and 300 GHz sources in LHD

et al. 2020

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Collective Thomson scattering (CTS) is one of attractive diagnostics for measuring locally and directly the fuel temperature and the velocity distribution of fast ions in fusion plasmas. A megawatt class source of millimeter or sub-millimeter waves is required to detect a weak scattered radiation superimposed on background radiation owing to electron cyclotron emissions (ECEs) from plasmas. Based on electron cyclotron resonance heating (ECRH) system with the frequencies of 77 GHz and 154 GHz in the Large Helical Device (LHD), the CTS diagnostic system has been developed to measure bulk ion temperatures from a few keV to ~10 keV and fast ions originated from 180 keV-neutral beam injection in the LHD. The measured CTS spectra and their time evolutions are analyzed with the electrostatic scattering theory. The bulk ion temperatures obtained from CTS spectra increase with the neutral beam injections and decrease with the heating terminated. The velocity map of simulated fast ions explains that the bumps on tail of measured CTS spectra are caused by the co-and counter-fast ions. A new prescription for anisotropic velocity distribution function is proposed. As for 154 GHz bands, the CTS spectrum broadenings for D and H plasmas are distinguished reasonably at the same temperature, and its ion temperatures are comparable to those of the charge exchange recombination spectroscopy. As reactor-relevant diagnostics, a 300 GHz gyrotron and a corresponding receiver system have been implemented in LHD to access high density plasmas with low background ECEs. The recent progress for CTS diagnostics and their spectrum analysis with the probe frequencies of 77 GHz, 154 GHz, and 300 GHz in the LHD experiments is described.

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Tomographic Reconstruction of Imaging Diagnostics with a Generative Adversarial Network

Cited by 4 publications

References 8 publications

Inward diffusion driven by low frequency fluctuations in self-organizing magnetospheric plasma

Inward diffusion driven by low frequency fluctuations in self-organizing magnetospheric plasma

From period to quasiperiod to chaos: A continuous spectrum of orbits of charged particles trapped in a dipole magnetic field

Collective Thomson scattering with 77, 154, and 300 GHz sources in LHD

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