Modified Phillips–Tikhonov regularization for plasma tomography

Lee, Seung Hun; Kim, Jung-Hee; Lee, J.H.; Choe, Wonho

doi:10.1016/j.cap.2009.10.017

Cited by 26 publications

(23 citation statements)

References 15 publications

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“…Thus, special attention has been paid to the computational tomographic (CT) reconstruction technique that was developed to mathematically reconstruct the local information from the set of line-integrated (projection) data because tomographic OES has become an attractive solution that yields the most complete picture of the plasma kinetics. In addition to plasma diagnostics [181][182][183], this technique has been well established, and it is actively used in the fields of medical imaging [184] and astronomy [185,186]. In most cases, the tomography algorithm seeks to reconstruct distributions over the region of interest with a limited number of lines of sights, and it can be formulated into an algebraic nonlinear optimization problem.…”

Section: Imaging Techniques (3-d or Cross-sectional)mentioning

confidence: 99%

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Park

Choe

Moon

et al. 2018

Advances in Physics: X

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Weakly ionized plasmas at or near 1 atm pressure, or atmospheric-pressure plasmas, have received increasing attention due to their scientific significance and potential for use in a variety of applications, particularly for medicine, agriculture, and food. However, there is a large imbalance between scientific research on plasma physics and applications, which is partly due to the considerable differences in the characteristics of these plasmas compared with those of low-pressure plasmas. This discrepancy is particularly related to the difficulty in performing plasma diagnostics for highly collisional plasmas. Information on electrons (such as the electron density and temperature) is essential since electrons play a dominant role in the generation of active species related to the physical and chemical processes inside the plasma. So far, limited diagnostics have been available for electrons such as Thomson scattering and optical emission diagnostics based on equilibrium models. Here, we review the available diagnostic methods along with their merits and limitations for characterizing electrons in weakly ionized collisional plasmas. Particular attention is paid to continuum radiation-based spectroscopy, which facilitates multidimensional imaging of electron density and temperature. The future impact of these plasmas on relevant fields (i.e. laboratory and industrial plasmas and their applications) is also addressed.

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Section: Imaging Techniques (3-d or Cross-sectional)mentioning

confidence: 99%

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Park

Choe

Moon

et al. 2018

Advances in Physics: X

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“…In this work, we adopted the Tikhonov regularization method to determine the inverse transformation. 12 The linear system defined by Eq. (1) is proposed to find a particular solution for f, which minimizes the following residual:…”

Section: Iedf Reconstruction Methodsmentioning

confidence: 99%

Observation of a high-energy tail in ion energy distribution in the cylindrical Hall thruster plasma

et al. 2014

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A novel method is presented to determine populations and ion energy distribution functions (IEDFs) of individual ion species having different charge states in an ion beam from the measured spectrum of an E Â B probe. The inversion of the problem is performed by adopting the iterative Tikhonov regularization method with the characteristic matrices obtained from the calculated ion trajectories. In a cylindrical Hall thruster plasma, an excellent agreement is observed between the IEDFs by an E Â B probe and those by a retarding potential analyzer. The existence of a high-energy tail in the IEDF is found to be mainly due to singly charged Xe ions, and is interpreted in terms of non-linear ion acceleration. V

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“…The output voltage of the three amplifiers was always saturated and the other amplifier only showed signal noise. 7,8 As described in Fig. Figure 3 shows the typical output voltage of the resistive bolometer for KSTAR.…”

Section: Methodsmentioning

confidence: 99%

First results of the resistive bolometers on KSTAR

Seo

Peterson

Lee

2010

Review of Scientific Instruments

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The resistive bolometers have been successfully installed in the midplane of L-port in Korea Superconducting Tokamak Advanced Research (KSTAR) device. The spatial and temporal resolutions, 4.5 cm and ∼1 kHz, respectively, enable us to measure the radial profile of the total radiated power from magnetically confined plasma at a high temperature through radiation and neutral particles. The radiated power was measured at all shots. Even at low plasma current, the bolometer signal was detectable. The electron cyclotron resonance heating (ECH) has been used in tokamak for ECH assisted start-up and plasma control by local heating and current drive. The detectors of resistive bolometer, near the antenna of ECH, are affected by electron cyclotron wave. The tomographic reconstruction, using the Phillips-Tikhonov regularization method, will be carried out for a major radial profile of the radiation emissivity of the circular cross-section plasma.

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Modified Phillips–Tikhonov regularization for plasma tomography

Cited by 26 publications

References 15 publications

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Electron characterization in weakly ionized collisional plasmas: from principles to techniques

Observation of a high-energy tail in ion energy distribution in the cylindrical Hall thruster plasma

First results of the resistive bolometers on KSTAR

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