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Artificially structured boundary plasma trap

Description: This article presents a computer simulation of single-species non-neutral plasma confinement using an artificially structured boundary. The results support the prospect of developing plasma space-charge based confinement, with an unmagnetized plasma of one species of charged particles confined by an electric field produced by an edge-confined plasma of a second species of charged particles.
Date: September 20, 2019
Creator: Hedlof, R. M. & Ordonez, Carlos A.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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Artificially structured boundary for confinement of effectively unmagnetized cryogenic antimatter plasmas

Description: The article is from conference proceedings that discuss an artificially structured boundary (ABS) considered to consist of a spatially periodic arrangement of electrostatically plugged magnetic cusps. As envisioned, a non-neutral positron plasma could be confined by an ASB along its edge, and the space charge of the positron plasma would serve to confine an antiproton plasma. If the conditions of the two-species plasma are suitable, production of antihydrogen via three-body recombination for an… more
Date: January 23, 2018
Creator: Hedlof, R. M. & Ordonez, Carlos A.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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Magnetic plasma expulsion

Description: The article presents one scheme for what is referred to as magnetic plasma expulsion, which would prevent the plasma from entering a given region. Magnetic plasma expulsion techniques may allow instrumentation access to the interiors of plasmas. Magnetic plasma expulsion techniques may also make alternative approaches for magnetic plasma confinement possible. Particle-in-cell simulation with the Warp code is used to study magnetic plasma expulsion. Some conditions for achieving magnetic plasma … more
Date: January 16, 2018
Creator: Phillips, R. E. & Ordonez, Carlos A.
Item Type: Refine your search to only Article
Partner: UNT College of Science
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An Electro- Magneto-static Field for Confinement of Charged Particle Beams and Plasmas

Description: A system is presented that is capable of confining an ion beam or plasma within a region that is essentially free of applied fields. An Artificially Structured Boundary (ASB) produces a spatially periodic set of magnetic field cusps that provides charged particle confinement. Electrostatic plugging of the magnetic field cusps enhances confinement. An ASB that has a small spatial period, compared to the dimensions of a confined plasma, generates electro- magneto-static fields with a short range.… more
Date: May 2014
Creator: Pacheco, Josè L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Dual levitated coils for antihydrogen production

Description: Article on theoretical and experimental efforts to use dual levitated coils to confine relatively large, cold, dense non-drifting recombining antihydrogen plasmas. The theoretical effort includes the development of a classical trajectory Monte Carlo simulation of confinement. The experimental effort includes levitation of a NdFeB permanent ring magnet, which produces a magnetic field that is qualitatively similar to the field that would be produced by the two coaxial superconducting magnetic co… more
Date: April 19, 2013
Creator: Wofford, Joshua D. & Ordonez, Carlos A.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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The Dependence of H-mode Energy Confinement and Transport on Collisionality in NSTX

Description: Understanding the dependence of confi nement on collisionality in tokamaks is important for the design of next-step devices, which will operate at collisionalities at least one order of magnitude lower than in present generation. A wide range of collisionality has been obtained in the National Spherical Torus Experiment (NSTX) by employing two different wall conditioning techniques, one with boronization and between-shot helium glow discharge conditioning (HeGDC+B), and one using lithium evapor… more
Date: November 28, 2012
Creator: S.M.. Kaye, S. Gerhardt, W. Guttenfelder, R. Maingi, R.E. Bell, A. Diallo, B.P. LeBlanc and M. Podesta
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Dependence of H-mode Energy Confinement and Transport on Collisionality in NSTX

Description: Understanding the dependence of confi nement on collisionality in tokamaks is important for the design of next-step devices, which will operate at collisionalities at least one order of magnitude lower than in present generation. A wide range of collisionality has been obtained in the National Spherical Torus Experiment (NSTX) by employing two different wall conditioning techniques, one with boronization and between-shot helium glow discharge conditioning (HeGDC+B), and one using lithium evapor… more
Date: November 27, 2012
Creator: S.M.. Kaye, S. Gerhardt, W. Guttenfelder, R. Maingi, R.E. Bell, A. Diallo, B.P. LeBlanc and M. Podesta
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Space-charge-based electrostatic plasma confinement involving relaxed plasma species

Description: In this article, a numerical study is reported on the equilibrium properties of a surface-emitted or edge-confined non-drifting plasma. A self-consistent finite-differences evaluation of the electrostatic potential is carried out for a non-neutral plasma that follows a Boltzmann density distribution.
Date: October 23, 2012
Creator: Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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Spatially Periodic Electromagnetic Force Field For Plasma Confinement and Control

Description: In this article, a theoretical understanding is developed of the single-particle reflection properties of a force field, considering the incident charged particles to have a non-drifting, isotropic velocity distribution. Classical trajectory Monte Carlo simulations and analytical modeling are employed. The initiation of an experimental effort to study force fields is described.
Date: April 17, 2012
Creator: Ordonez, Carlos A.; Pacheco, J. L. & Weathers, Duncan L.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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L-H Threshold Studies in NSTX

Description: Recent experiments in the low aspect ratio National Spherical Torus Experiment (NSTX) have been run in support of the high priority ITER and ITPA issue of access to the H-mode. Specifically, a series of experiments showed reduced power threshold values for deuterium vs helium plasmas, and for plasmas with lower current, lower triangularity and with lithium conditioning. Application of n=3 fields at the plasma edge resulted in higher power thresholds. To within the constraints of temporal and sp… more
Date: September 6, 2011
Creator: Kaye, S. M.; Battaglia, D.; Bell, R. E.; Chang, C. S.; Hosea, J.; Kugel, H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laser ion source with long pulse width for RHIC-EBIS

Description: The Electron Beam Ion Source (EBIS) at Brookhaven National Laboratory is a new heavy ion-projector for RHIC and NASA Space Radiation Laboratory. Laser Ion Source (LIS) with solenoid can supply many kinds of ion from solid targets and is suitable for long pulse length with low current as ion provider for RHIC-EBIS. In order to understand a plasma behavior for fringe field of solenoid, we measure current, pulse width and total ion charges by a new ion probe. The experimental result indicates that… more
Date: March 28, 2011
Creator: Kondo, K.; Kanesue, T. & Okamura, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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23rd IAEA Fusion Energy Conference: Summary Of Sessions EX/C and ICC

Description: An overview is given of recent experimental results in the areas of innovative confinement concepts, operational scenarios and confinement experiments as presented at the 2010 IAEA Fusion Energy Conference. Important new findings are presented from fusion devices worldwide, with a strong focus towards the scientific and technical issues associated with ITER and W7-X devices, presently under construction.
Date: January 5, 2011
Creator: Hawryluk, Richard J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Midsize Tokamak As Fast Track To Burning Plasmas

Description: This paper presents a midsize tokamak as a fast track to the investigation of burning plasmas. It is shown that it could reach large values of energy gain (≥10) with only a modest improvement in confinement over the scaling that was used for designing the International Thermonuclear Experimental Reactor (ITER). This could be achieved by operating in a low plasma recycling regime that experiments indicate can lead to improved plasma confinement. The possibility of reaching the necessary conditio… more
Date: July 14, 2010
Creator: Mazzucato, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Quiet Periods in Edge Turbulence Preceding the L-H Transition in NSTX

Description: This paper describes the first observations in NSTX of ‘quiet periods’ in the edge turbulence preceding the L-H transition, as diagnosed by the GPI diagnostic near the outer midplane separatrix. During these quiet periods the GPI Dα light emission pattern was transiently similar to that seen during Hmode, i.e. with a relatively small fraction of the GPI light emission located outside the separatrix. These quiet periods had a frequency of ~3 kHz for at least 30 msec before the L-H transition, an… more
Date: April 26, 2010
Creator: Zweben, S.; Hager, R.; Hallatschek, K.; Kaye, S. M.; Munsat, T.; Poli, F. M. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Feasibility Studies of Alpha-Channeling in Mirror Machines

Description: The linear magnetic trap is an attractive concept both for fusion reactors and for other plasma applications due to its relative engineering simplicity and high-beta operation. Applying the α- channeling technique to linear traps, such as mirror machines, can benefit this concept by efficiently redirecting α particle energy to fuel ion heating or by otherwise sustaining plasma confinement, thus increasing the effective fusion reactivity. To identify waves suitable for α-channeling a rough optim… more
Date: March 19, 2010
Creator: Zhmoginov, A. I. & Fisch, N. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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MHD-Stabilization of Axisymmetric Mirror Systems Using Pulsed ECRH

Description: This paper, part of a continuing study of means for the stabilization of MHD interchange modes in axisymmertric mirror-based plasma confinement systems, is aimed at a preliminary look at a technique that would employ a train of plasma pressure pulses produced by ECRH to accomplish the stabilization. The purpose of using sequentially pulsed ECRH rather than continuous-wave ECRH is to facilitate the localization of the heated-electron plasma pulses in regions of the magnetic field with a strong p… more
Date: November 20, 2009
Creator: Post, R F
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Importance of Plasma Response to Non-axisymmetric Perturbations in Tokamaks

Description: Tokamaks are sensitive to deviations from axisymmetry as small as δB=B0 ~ 10-4. These non-axisymmetric perturbations greatly modify plasma confinement and performance by either destroying magnetic surfaces with subsequent locking or deforming magnetic surfaces with associated non-ambipolar transport. The Ideal Perturbed Equilibrium Code (IPEC) calculates ideal perturbed equilibria and provides important basis for understanding the sensitivity of tokamak plasmas to perturbations. IPEC calculatio… more
Date: April 22, 2009
Creator: Jong-kyu Park, Allen H. Boozer, Jonathan E. Menard, Andrea M. Garofalo, Michael J. Schaffer, Richard J. Hawryluk, Stanley M. Kaye, Stefan P. Gerhardt, Steve A. Sabbagh, and the NSTX Team
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Center for Multiscale Plasma Dynamics, Final Report

Description: The University of Michigan participated in the joint UCLA/Maryland fusion science center focused on plasma physics problems for which the traditional separation of the dynamics into microscale and macroscale processes breaks down. These processes involve large scale flows and magnetic fields tightly coupled to the small scale, kinetic dynamics of turbulence, particle acceleration and energy cascade. The interaction between these vastly disparate scales controls the evolution of the system. The … more
Date: October 13, 2008
Creator: Gombosi, Tamas I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Alpha Channeling in a Rotating Plasma

Description: The wave-particle α-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with α particles in a mirror machine with E × B rotation to diffuse the α particles along constrained paths in phase space. Of major interest is that the α-particle energy, in addition to amplifying the RF waves, can directly enhance the rotation energy which in turn provides additional plasma confinement in centrifugal fusion reactors. An ancillary benefit is the ra… more
Date: September 23, 2008
Creator: Fisch, Abraham J. Fetterman and Nathaniel J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energetic Particle-induced Geodesic Acoustic Mode

Description: A new energetic particle-induced Geodesic Acoustic Mode (EGAM) is shown to exist. The mode frequency, mode structure, and mode destabilization are determined non-perturbatively by energetic particle kinetic effects. In particular the EGAM frequency is found to be substantially lower than the standard GAM frequency. The radial mode width is determined by the energetic particle drift orbit width and can be fairly large for high energetic particle pressure and large safety factor. These results ar… more
Date: September 12, 2008
Creator: Fu, G. Y.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fully Electromagnetic Nonlinear Gyrokinetic Equations for Tokamak Edge Turbulence

Description: An energy conserving set of the fully electromagnetic nonlinear gyrokinetic Vlasov equation and Maxwell's equations, which is applicable to both L-mode turbulence with large amplitude and H-mode turbulence in the presence of high E Χ B shear has been derived. The phase-space action variational Lie perturbation method ensures the preservation of the conservation laws of the underlying Vlasov-Maxwell system. Our generalized ordering takes ρ[sub ]i [\sub]<< ρϑ¡ ~ LE ~ Lp << R (here ρ[sub ]i [\sub]… more
Date: August 27, 2008
Creator: Hahm, T.S.; Wang, Lu, & Madsen, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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