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Title: Geometric scalings for the electrostatically driven helical plasma state

Abstract

A new plasma state has been investigated [Akcay et al., Phys. Plasmas 24, 052503 (2017)], with a uniform applied axial magnetic field in a periodic cylinder of length $L=2πR$, driven by helical electrodes. The drive is single helicity, depending on $mθ+kz=mθ-nζ$, where $ζ=z/R$ and $k=-n/R$. For strong $(m,n)=(1,1)$ drive, the state was found to have a strong axial mean current density, with a mean-field safety factor $$q_0(r)$$ just above the pitch of the electrodes $m/n=1$ in the interior. This state has possible applications to DC electrical transformers and tailoring of the current profile in tokamaks. Here, we study two geometric issues of interest for these applications: (i) scaling of properties with the plasma length or aspect ratio and (ii) behavior for different helicities, specifically $(m,n)=(1,n)$ for n > and $(m,n)=(2,1)$.

Authors:
 [1];  [1];  [1];  [1]
  1. Tibbar Plasma Technologies, Los Alamos, NM (United States)
Publication Date:
Research Org.:
Tibbar Plasma Technologies, Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1524594
Alternate Identifier(s):
OSTI ID: 1414984
Grant/Contract Number:  
AR0000677
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 12; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Akçay, Cihan, Finn, John M., Nebel, Richard A., and Barnes, Daniel C. Geometric scalings for the electrostatically driven helical plasma state. United States: N. p., 2017. Web. doi:10.1063/1.5011774.
Akçay, Cihan, Finn, John M., Nebel, Richard A., & Barnes, Daniel C. Geometric scalings for the electrostatically driven helical plasma state. United States. doi:10.1063/1.5011774.
Akçay, Cihan, Finn, John M., Nebel, Richard A., and Barnes, Daniel C. Wed . "Geometric scalings for the electrostatically driven helical plasma state". United States. doi:10.1063/1.5011774. https://www.osti.gov/servlets/purl/1524594.
@article{osti_1524594,
title = {Geometric scalings for the electrostatically driven helical plasma state},
author = {Akçay, Cihan and Finn, John M. and Nebel, Richard A. and Barnes, Daniel C.},
abstractNote = {A new plasma state has been investigated [Akcay et al., Phys. Plasmas 24, 052503 (2017)], with a uniform applied axial magnetic field in a periodic cylinder of length $L=2πR$, driven by helical electrodes. The drive is single helicity, depending on $mθ+kz=mθ-nζ$, where $ζ=z/R$ and $k=-n/R$. For strong $(m,n)=(1,1)$ drive, the state was found to have a strong axial mean current density, with a mean-field safety factor $q_0(r)$ just above the pitch of the electrodes $m/n=1$ in the interior. This state has possible applications to DC electrical transformers and tailoring of the current profile in tokamaks. Here, we study two geometric issues of interest for these applications: (i) scaling of properties with the plasma length or aspect ratio and (ii) behavior for different helicities, specifically $(m,n)=(1,n)$ for n > and $(m,n)=(2,1)$.},
doi = {10.1063/1.5011774},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 12,
volume = 24,
place = {United States},
year = {2017},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

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Cited by: 1 work
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Figures / Tables:

FIG. 1 FIG. 1: The reciprocal of the mean safety factor on the axis, 1/q0(0), and the O-point position rO, as functions of the applied helical potential ϕ0 for different aspect ratios R/rw, with (m, n) = (1, 1). The dependence of these two quantities on ϕ0 exhibits little sensitivity to R/rw,more » above ϕ0 = ϕmin = 0.1.« less

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Works referenced in this record:

Electrostatically driven helical plasma state
journal, May 2017

  • Akçay, Cihan; Finn, John M.; Nebel, Richard A.
  • Physics of Plasmas, Vol. 24, Issue 5
  • DOI: 10.1063/1.4981384

Semi-implicit magnetohydrodynamic calculations
journal, June 1987


Single and multiple helicity Ohmic states in reversed‐field pinches
journal, May 1992

  • Finn, John M.; Nebel, Rick; Bathke, Charles
  • Physics of Fluids B: Plasma Physics, Vol. 4, Issue 5
  • DOI: 10.1063/1.860082

Review of spheromak research
journal, June 1994


    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.