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Title: Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap

Authors:
 [1];  [1]
  1. Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1411983
Grant/Contract Number:
FC03- 02NA00057
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 21; Related Information: CHORUS Timestamp: 2017-12-07 11:17:40; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Cordaro, S. W., and Bott-Suzuki, S. C. Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap. United States: N. p., 2017. Web. doi:10.1063/1.5002698.
Cordaro, S. W., & Bott-Suzuki, S. C. Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap. United States. doi:10.1063/1.5002698.
Cordaro, S. W., and Bott-Suzuki, S. C. 2017. "Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap". United States. doi:10.1063/1.5002698.
@article{osti_1411983,
title = {Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap},
author = {Cordaro, S. W. and Bott-Suzuki, S. C.},
abstractNote = {},
doi = {10.1063/1.5002698},
journal = {Journal of Applied Physics},
number = 21,
volume = 122,
place = {United States},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 7, 2018
Publisher's Accepted Manuscript

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  • In the context of low temperature plasma research, we propose a wall current probe to determine the local charged particle fluxes flowing to the chamber walls. This non-intrusive planar probe consists of an array of electrode elements which can be individually biased and for which the current can be measured separately. We detail the probe properties and present the ability of the diagnostic to be used as a space and time resolved measurement of the ion and electron current density at the chamber walls. This diagnostic will be relevant to study the electron transport in magnetized low-pressure plasmas.
  • A modified {dot {ital B}} circuit design has been implemented as part of a miniature magnetic probe array for the Coaxial Plasma Source experiment [R. M. Mayo {ital et} {ital al}., Plasma Sources Sci. Technol. {bold 4}, 47 (1995)] at the North Carolina State University. This facility is currently being used for the generation of energetic plasma flows to allow laboratory study of magnetogasdynamics with particular emphasis on the importance of the Hall effect [D. C. Black {ital et} {ital al}., Phys. Plasma {bold 1}, 3115 (1994)] and plasma microinstabilities [R. M. Mayo {ital et} {ital al}., Phys. Plasma {boldmore » 2}, 337 (1995)] to plasma transport in coaxial plasma sources. The miniature magnetic probe array consists of ten spatially separated coils wound on an Acetal form of dimensions 2.38 cm by 0.32 cm by 0.32 cm. At five positions, with roughly 0.32 cm separation, two mutually perpendicular coils are wound to measure the magnetic field in the {cflx {theta}} and {cflx {ital z}} directions. The modification to the signal processing circuitry consists of the use of a step-up transformer to boost the probe signal prior to filtering and acquiring the signal at the data acquisition system. This additional means of amplifying the signal allows for reduction in the size of the probe, and thus helps minimize the perturbing effect of the magnetic probe on the plasma. An additional advantage of using a signal transformer is that it provides electrical isolation between the experiment and the data acquisition system. {copyright} {ital 1996 American Institute of Physics.}« less
  • The experimentally determined current-voltage characteristics of high-T{sub c} superconducting ceramics exhibiting the {open_quotes}peak-effect{close_quotes} in the magnetic field dependence of the transport critical-current density were described in terms of thermally activated flux creep at grain boundaries; taking into account the collective pinning of intergranular vortices. The peak effect was explained by considering the increase of the intergrain pinning potential at intermediate fields through the interaction of intergranular (Josephson type) vortices and intragranular (Abrikosov) vortices. The magnetic field dependences of the effective pinning potential and of the collective pinning exponent were experimentally determined, and the features of the I-V curves were explainedmore » through these dependences.« less
  • A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 A is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n{sub e}{>=} 10{sup 14} cm{sup -3}) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integratedmore » profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.« less