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Title: Laser collisional induced fluorescence electron density measurements as a function of ring bias and the onset of anode spot formation in a ring cusp magnetic field

Abstract

In this paper, two-dimensional electron density measurements are made in a magnetic ring cusp discharge using laser collisional induced fluorescence. The magnet rings are isolated from the anode structure such that they can be biased independently in order to modulate electron flows through the magnetic cusps. Electron density images are captured as a function of bias voltage in order to assess the effects of current flow through the cusp on the spatial extent of the cusp. We anticipated that for a fixed current density being funneled through the magnetic cusp, the leak width would necessarily increase. Unexpectedly, the leak width, as measured by LCIF images, does not increase. This suggests that the current density is not constant, and that possibly either electrons are being heated or additional ionization events are occurring within the cusp. Spatially resolving electron temperature would be needed to determine if electrons are being heated within the cusp. Finally, we also observe breakdown of the anode magnetosheath and formation of anode spots at high bias voltage.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Nuclear Engineering and Radiological Sciences
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Workforce Development for Teachers and Scientists (WDTS)
OSTI Identifier:
1474090
Report Number(s):
SAND-2018-10182J
Journal ID: ISSN 1361-6595; 667942
Grant/Contract Number:  
NA0003525; SC0014664
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Plasma Sources Science and Technology
Additional Journal Information:
Journal Volume: 27; Journal Issue: 5; Journal ID: ISSN 1361-6595
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; magnetized sheath; laser collisional induced fluorescence; anode spot; magnetic cusp

Citation Formats

Arthur, N. A., Foster, J. E., and Barnat, E. V. Laser collisional induced fluorescence electron density measurements as a function of ring bias and the onset of anode spot formation in a ring cusp magnetic field. United States: N. p., 2018. Web. doi:10.1088/1361-6595/aac309.
Arthur, N. A., Foster, J. E., & Barnat, E. V. Laser collisional induced fluorescence electron density measurements as a function of ring bias and the onset of anode spot formation in a ring cusp magnetic field. United States. https://doi.org/10.1088/1361-6595/aac309
Arthur, N. A., Foster, J. E., and Barnat, E. V. Tue . "Laser collisional induced fluorescence electron density measurements as a function of ring bias and the onset of anode spot formation in a ring cusp magnetic field". United States. https://doi.org/10.1088/1361-6595/aac309. https://www.osti.gov/servlets/purl/1474090.
@article{osti_1474090,
title = {Laser collisional induced fluorescence electron density measurements as a function of ring bias and the onset of anode spot formation in a ring cusp magnetic field},
author = {Arthur, N. A. and Foster, J. E. and Barnat, E. V.},
abstractNote = {In this paper, two-dimensional electron density measurements are made in a magnetic ring cusp discharge using laser collisional induced fluorescence. The magnet rings are isolated from the anode structure such that they can be biased independently in order to modulate electron flows through the magnetic cusps. Electron density images are captured as a function of bias voltage in order to assess the effects of current flow through the cusp on the spatial extent of the cusp. We anticipated that for a fixed current density being funneled through the magnetic cusp, the leak width would necessarily increase. Unexpectedly, the leak width, as measured by LCIF images, does not increase. This suggests that the current density is not constant, and that possibly either electrons are being heated or additional ionization events are occurring within the cusp. Spatially resolving electron temperature would be needed to determine if electrons are being heated within the cusp. Finally, we also observe breakdown of the anode magnetosheath and formation of anode spots at high bias voltage.},
doi = {10.1088/1361-6595/aac309},
url = {https://www.osti.gov/biblio/1474090}, journal = {Plasma Sources Science and Technology},
issn = {1361-6595},
number = 5,
volume = 27,
place = {United States},
year = {2018},
month = {5}
}

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Works referenced in this record:

Cusp width and power flow study at a high power magnetic multipole ion source
journal, January 1987


The electron spatial distribution and leak width in a magnetic cusp
journal, February 2014


Plasma confinement by localized cusps
journal, January 1976


Lifetime measurement of the 1 s 5 metastable state of argon and krypton with a magneto-optical trap
journal, June 1993


Theory of sheaths near positively biased electrodes
conference, June 2016


Leak widths resulting from plasma diffusion in a magnetic cusp
journal, April 1988


Ion Thruster Discharge Performance per Magnetic Field Topography
conference, June 2012


Two-dimensional mapping of electron densities and temperatures using laser-collisional induced fluorescence
journal, September 2010


Electron density measurement in a rf helium plasma by laser‐collision induced fluorescence method
journal, September 1996


Plasma electron density measurements by the laser- and collision-induced fluorescence method
journal, September 1983


2D laser-collision induced fluorescence in low-pressure argon discharges
journal, September 2015


Measurement of rate coefficients for electron-atom collisions in a helium plasma by laser-induced fluorescence
journal, September 1999


Two-dimensional laser collision-induced fluorescence measurements of plasma properties near an RF plasma cathode extraction aperture
journal, October 2012


Quenching and excitation transfer in the n = 3 helium sublevels in a low-pressure glow discharge
journal, January 1980


Primary electron confinement measurement in a multidipole device
journal, May 1978


Equilibrium states of anodic double layers
journal, April 2009


Emissive probes
journal, November 2011


Rayleigh scattering and redistribution of radiation in Helium in a magnetic multipole plasma source
conference, January 2001


Theory and simulation of anode spots in low pressure plasmas
journal, November 2017


Ion source discharge performance and stability
journal, January 1982


Characterization of a cylindrical ring-cusp ion source with electrically isolated magnet rings
journal, March 2017


Metastable Helium: A New Determination of the Longest Atomic Excited-State Lifetime
journal, July 2009


Behaviour of laser-produced high-β plasmas in a spindle-cusp magnetic container
journal, May 1978


Internal Plasma Properties and Enhanced Performance of 8-Centimeter Ion Thruster Discharge
journal, March 2001


Electron-impact excitation and ionization cross sections for ground state and excited helium atoms
journal, July 2008


Rayleigh scattering and redistribution of radiation in He I plasmas: Measurements and calculations
journal, October 2002


Plasma Leakage Through a Low- β Line Cusp
journal, August 1975


Density Measurement of Helium Metastable Atoms in a Plasma by the Laser-Induced Fluorescence Method
journal, March 1984


The effect of a magnetic field gradient on anode double layers
journal, April 1992


Magnetic Multipole Containment of Large Uniform Collisionless Quiescent Plasmas
journal, June 1973


Improved ion containment using a ring-cusp ion thruster
conference, February 2013


Improved ion containment using a ring-cusp ion thruster
journal, September 1984


Quenching and excitation transfer in the n = 3 helium sublevels in a low-pressure glow discharge
journal, January 1980


Rayleigh scattering and redistribution of radiation in He I plasmas: Measurements and calculations
journal, October 2002


Density Measurement of Helium Metastable Atoms in a Plasma by the Laser-Induced Fluorescence Method
journal, March 1984


Metastable Helium: A New Determination of the Longest Atomic Excited-State Lifetime
journal, July 2009


Lifetime measurement of the 1 s 5 metastable state of argon and krypton with a magneto-optical trap
journal, June 1993


Theory of sheaths near positively biased electrodes
conference, June 2016


Plasma Leakage Through a Low- β Line Cusp
journal, August 1975