Two-Fluid Equilibrium Considerations of Te/Ti » 1, Collisionless ST Plasmas Sustained by RF Electron Heating

Yueng Kay Martin Peng, Akio Ishida, Yuichi Takase, Akira Ejiri, Naoto Tsujii, Takashi Maekawa, Masaki Uchida, Hideki Zushi, Kazuaki Hanada, Makoto Hasegawa

Research output: Contribution to journalArticle

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Abstract

A solution of two-fluid (electron and ion), axisymmetric equilibrium is presented that approximates solenoidfree plasmas sustained only by RF electron heating that are recently studied in TST-2, LATE, QUEST. These plasmas indicate presence of orbit-confined energetic electrons carrying substantial toroidal current outside the last closed flux surface (LCFS); Te/Ti » 1 and low collisionality at modest densities within LCFS; and likely a positive plasma potential relative to the conductive vacuum vessel. A system of nonlinear second-order partial differential and algebraic equations constraining six functionals of poloidal magnetic flux or canonical angular momentum are solved. An example plasma measured in TST-2 is used to guide, by trial and error, the selection of these functionals to find appropriate solutions, while assuming peaked plasma profiles and 60% toroidal current within the LCFS. The numerical equilibrium obtained indicates a substantial ion toroidal flow and electrostatic potential so that the ion ∇pi, centrifugal, and electrostatic forces of nearly equal magnitudes combine to balance the Ji × B force, differently from the massless electron fluid that satisfies ∇pe = Je × B. The calculated properties suggest additional measurements needed to refine the choices of the functional forms and improve the two-fluid equilibrium fit to such plasmas.

Original languageEnglish
Article number3403146
JournalPlasma and Fusion Research
Volume9
Issue numberSpecialIssue2
DOIs
Publication statusPublished - Jan 1 2014

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collisionless plasmas
heating
fluids
electrons
functionals
electrostatics
ions
centrifugal force
plasma potentials
partial differential equations
vessels
magnetic flux
angular momentum
orbits
vacuum
profiles

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Two-Fluid Equilibrium Considerations of Te/Ti » 1, Collisionless ST Plasmas Sustained by RF Electron Heating. / Peng, Yueng Kay Martin; Ishida, Akio; Takase, Yuichi; Ejiri, Akira; Tsujii, Naoto; Maekawa, Takashi; Uchida, Masaki; Zushi, Hideki; Hanada, Kazuaki; Hasegawa, Makoto.

In: Plasma and Fusion Research, Vol. 9, No. SpecialIssue2, 3403146, 01.01.2014.

Research output: Contribution to journalArticle

Peng, YKM, Ishida, A, Takase, Y, Ejiri, A, Tsujii, N, Maekawa, T, Uchida, M, Zushi, H, Hanada, K & Hasegawa, M 2014, 'Two-Fluid Equilibrium Considerations of Te/Ti » 1, Collisionless ST Plasmas Sustained by RF Electron Heating', Plasma and Fusion Research, vol. 9, no. SpecialIssue2, 3403146. https://doi.org/10.1585/pfr.9.3403146
Peng, Yueng Kay Martin ; Ishida, Akio ; Takase, Yuichi ; Ejiri, Akira ; Tsujii, Naoto ; Maekawa, Takashi ; Uchida, Masaki ; Zushi, Hideki ; Hanada, Kazuaki ; Hasegawa, Makoto. / Two-Fluid Equilibrium Considerations of Te/Ti » 1, Collisionless ST Plasmas Sustained by RF Electron Heating. In: Plasma and Fusion Research. 2014 ; Vol. 9, No. SpecialIssue2.
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