Particle-confinement criteria for axisymmetric field-reversed magnetic configurations

Hsiao, Ming-Yuan; Miley, George H.

doi:10.1088/0029-5515/24/8/008

Cited by 25 publications

(9 citation statements)

References 4 publications

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“…The existence of such a boundary was first recognized for Astron systems 11 and later in the context of FRCs per se. 18 The latter derived a kinetic "confinement boundary" illustrated in Fig. 1 H þ x cj P h < 0;…”

Section: Kinetic Ion Modelmentioning

confidence: 99%

Hybrid equilibria of field-reversed configurations

Steinhauer

2011

Physics of Plasmas

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This paper presents the first detailed model of hybrid equilibria relevant to field-reversed configuration experiments, leading to a system of equations that are solved for a range of fully two-dimensional equilibria. Several features of these highly kinetic objects are explored. The range of equilibria is primarily dependent on a single free parameter related to the flow shear. The level of flow shear has a profound effect on the structure, especially near the separatrix. This likely has a strong influence on both stability and transport properties. Higher flow shear is favorable in every respect. The key factor behind the influence of flow shear is the relatively rapid end loss of unconfined ions. Differences between hybrid and static-fluid equilibrium models are highlighted, including the integrity of surface functions, the effect of flow shear, and the scrape-off layer thickness.

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Section: Kinetic Ion Modelmentioning

confidence: 99%

Hybrid equilibria of field-reversed configurations

Steinhauer

2011

Physics of Plasmas

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“…Particle loss can induce a plasma rotation in the ion diamagnetic direction. Indeed, examination of particle orbits reveals [256,323] that particles lost out of the FRC separatrix have a preferred sign (negative) of their angular momentum. Therefore, as they leave, the remaining plasma gradually acquires a net (positive) rotational motion.…”

Section: Origin Of the Rotationmentioning

confidence: 99%

Field reversed configurations

1988

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The review is devoted to field reversed configurations and to the related field reversed mirrors; both are compact toroids with little or no toroidal magnetic field. Experimental and theoretical results on the formation, equilibrium, stability and confinement properties of these plasmas are presented. Although they have been known for about three decades, field reversed configurations have been studied intensively only in recent years. This renewed interest is due to the unusual fusion reactor potential of these high beta plasmas and also to their surprising macroscopic stability. At the present time, field reversed configurations appear to be completely free of gross instabilities and show relatively good confinement. The primary research goal for the near future is to retain these favourable properties in a less kinetic regime. Other important issues include the development of techniques for slow formation and stability, and a clearer assessment of the confinement scaling laws.

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“…As the temperature outside the separatrix decreases, the average end loss time ͗1/ʈ͘ Ϫ1 decreases and the difference from ͗ʈ͘ MHD increases. If there are particle losses that are not ascribed to the cross-field diffusion, such as particle loss process 21,22 into the loss cone in the (H,p ) plane, the difference between ͗1/ʈ͘ Ϫ1 and ͗ʈ͘ MHD diminishes. The reason for this is that the effective particle confinement time, N , for cross-field diffusion in Eq.…”

Section: Discussionmentioning

confidence: 99%

Particle end loss in the edge plasma of a field-reversed configuration

et al. 1998

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Plasma parameters, particle end loss flux, flow velocity, and pressure are measured using a radial array of magnetic probes and directional electrostatic probes, in order to investigate particle loss processes in the edge layer of a field-reversed configuration (FRC). A plasma flow toward the end region is detected outside the separatrix between the axial midplane and the end region. The exhaust flow is also found in the end region. These results imply that particles are lost radially across the separatrix and then axially to the end. Measured flow velocity in the end region agrees within an error of 20% with the fluid-theory prediction, in which isentropy and axial momentum balance along magnetic flux tubes are assumed. The existence of the sonic condition in the end region is also suggested, analogous to ordinary fluid flow in a nozzle. The magnetic flux embedded in the edge layer of the confinement region and in the end region agrees within an error of 30%. These results indicate the applicability of the magnetohydrodynamics (MHD) theory for particle end loss. The end loss time along the open field agrees with the MHD prediction within an error of 20%. The measured particle loss flux from the end region is explained by the MHD theory within an error of 20%. The plasma outside the separatrix is considered to behave as hydrodynamic flow through the magnetic loss channel, contrary to the previous work [L. C. Steinhaur, Phys. Fluids 29, 3379 (1986)]. It seems that the magnetic mirror field improves the particle confinement in the edge plasma of the FRC and thus assist the FRC confinement as previously predicted [Slough et al., Nucl. Fusion 24, 1537 (1984)].

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Particle-confinement criteria for axisymmetric field-reversed magnetic configurations

Cited by 25 publications

References 4 publications

Hybrid equilibria of field-reversed configurations

Hybrid equilibria of field-reversed configurations

Field reversed configurations

Particle end loss in the edge plasma of a field-reversed configuration

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