Outward electron orbit extending to inward part of closed helical magnetic surfaces surrounded by shifted negative space potential

Himura, Haruhiko; Nakamura, Katsumi; Masamune, S.; Isobe, M.; Shimizu, A.

doi:10.1063/1.3339911

Cited by 3 publications

(8 citation statements)

References 17 publications

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“…In addition, the numerical code has taken into account the recently estabauthor's e-mail: himura@kit.ac.jp lished fact that the equipotential surfaces do not coincide with the HMS [2]. Recently, we found inward electron orbits extending to the inner part of the closed HMS region [7]. The obtained results have clearly shown that in the SMR, the pitch angle of the injected electron changes considerably while it circulates there.…”

Section: Introductionmentioning

confidence: 82%

“…This direction is consistent with that of the ∇B drift of electrons. Therefore, we concluded that this inward penetration is caused by the drift motion of a helically trapped electron [7]. Figure 4 shows the time evolution of the principal parameters of the helically trapped electron before and after reflection at the lower region.…”

Section: Brief Review Of Electron Penetrationmentioning

confidence: 89%

“…Another established fact is that φ s on each HMS is never constant. Therefore, we assume symmetrical equipotential surfaces (EPS) of φ s that are exactly the same as the elliptical HMS of the CHS, except that the center of the EPS is shifted from that of the HMS by ∼ 2 cm [7].…”

Section: Brief Review Of Electron Penetrationmentioning

confidence: 99%

“…Details are available in Ref. [7]. An electron is initially injected into the SMR, where a shifted negative φ s is assumed.…”

Section: Brief Review Of Electron Penetrationmentioning

confidence: 99%

“…In fact, the particle is trapped in the foot of the finite negative φ s region in the SMR. This result indicates that φ s in the SMR acts as a potential barrier to the electron [7]. However, no details of how the electron reflects at the potential barrier in the SMR have been determined yet.…”

Section: Introductionmentioning

confidence: 97%

See 4 more Smart Citations

Role of Negative Potential Barrier Formed by Electrons Confined in the Stochastic Magnetic Region of Helical Nonneutral Plasmas

Himura

Isobe

Shimizu

et al. 2010

Plasma and Fusion Research

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Nonneutral plasmas confined in the helical magnetic surface (HMS) region can be produced by injecting electrons from outside the last closed flux surface (LCFS). Recently, we numerically calculated outward electron orbits that extend to the inner HMS region. Once it penetrates the HMS region, the injected electron is never lost to the chamber wall, because the negative self-electric potential φ s in the stochastic magnetic region (SMR) acts as a potential barrier. Remarkably, during the reflection process at the potential barrier, the electron is still trapped in the foot of the negative φ s region, although it completely overcomes the SMR. The electron then resumes inward movement across the HMS.

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Section: Introductionmentioning

confidence: 82%

Section: Brief Review Of Electron Penetrationmentioning

confidence: 89%

Section: Brief Review Of Electron Penetrationmentioning

confidence: 99%

“…Details are available in Ref. [7]. An electron is initially injected into the SMR, where a shifted negative φ s is assumed.…”

Section: Brief Review Of Electron Penetrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Role of Negative Potential Barrier Formed by Electrons Confined in the Stochastic Magnetic Region of Helical Nonneutral Plasmas

Himura

Isobe

Shimizu

et al. 2010

Plasma and Fusion Research

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Counter differential rigid-rotation equilibrium of electrically non-neutral two-fluid plasma with finite pressure

2021

Self Cite

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We derive the two-dimensional counter-differential rotation equilibria of two-component plasmas, composed of both ion and electron ( $e^-$ ) clouds with finite temperatures, for the first time. In the equilibrium found in this study, as the density of the $e^{-}$ cloud is always larger than that of the ion cloud, the entire system is a type of non-neutral plasma. Consequently, a bell-shaped negative potential well is formed in the two-component plasma. The self-electric field is also non-uniform along the $r$ -axis. Moreover, the radii of the ion and $e^{-}$ plasmas are different. Nonetheless, the pure ion as well as $e^{-}$ plasmas exhibit corresponding rigid rotations around the plasma axis with different fluid velocities, as in a two-fluid plasma. Furthermore, the $e^{-}$ plasma rotates in the same direction as that of $\boldsymbol {E \times B}$ , whereas the ion plasma counter-rotates overall. This counter-rotation is attributed to the contribution of the diamagnetic drift of the ion plasma because of its finite pressure.

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A Proposed Test of Extended MHD Plasmas by Merging of Lithium Ion Plasmas with Pure Electron Plasmas

Himura

2010

IEEJ Trans. FM

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Haruhiko Himura * , Non-member Recently, extended MHD plasmas have been proposed, especially in both theoretical and computational fields of plasma physics. To test those experimentally, we propose a new project using two nonneutral plasmas: pure ion and electron plasmas. The experiment is performed on a linear machine in which a pair of positive and negative electrostatic potential wells is externally produced. In the positive potential well, an 7 Li + plasma is confined, while an electron plasma in the negative potential one. Then, those nonneutral plasmas are merged into an extended MHD plasma. The most remarkable advantage to employing nonneutral plasmas is that the ion skin depth, that is a typical scale length of the extended MHD plasmas, can be extended to the plasma radius. This actually alleviates experimental difficulties in diagnosing properties of the extended MHD plasmas. With precisely controlling densities of both pure 7 Li + ion and electron plasmas, the proposed method may explore an unrevealed research field of extended MHD plasmas.

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Outward electron orbit extending to inward part of closed helical magnetic surfaces surrounded by shifted negative space potential

Cited by 3 publications

References 17 publications

Role of Negative Potential Barrier Formed by Electrons Confined in the Stochastic Magnetic Region of Helical Nonneutral Plasmas

Role of Negative Potential Barrier Formed by Electrons Confined in the Stochastic Magnetic Region of Helical Nonneutral Plasmas

Counter differential rigid-rotation equilibrium of electrically non-neutral two-fluid plasma with finite pressure

A Proposed Test of Extended MHD Plasmas by Merging of Lithium Ion Plasmas with Pure Electron Plasmas

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