76 Matching Results

This system will be undergoing maintenance April 18th between 9:00AM and 12:00PM CDT.

Search Results

Advanced search parameters have been applied.
in subjects: "Magnetic Field Reversal"  
Results: 1 - 24 next
open access

Maintaining the closed magnetic-field-line topology of a field-reversed configuration (FRC) with the addition of static transverse magnetic fields

Description: The effects on magnetic-field-line structure of adding various static transverse magnetic fields to a Solovev-equilibrium field-reversed configuration is examined. It is shown that adding fields that are anti-symmetric about the axial mid-plane maintains the closed field-line structure, while adding fields with planar or helical symmetry opens the field structure. Anti-symmetric modes also introduce pronounced shear.
Date: January 13, 2000
Creator: Cohen, S.A. & Milroy, R.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Calculations of alpha particle loss for reversed magnetic shear in the Tokamak Fusion Test Reactor

Description: Hamiltonian coordinate, guiding center code calculations of the toroidal field ripple loss of alpha particles from a reversed shear plasma predict both total alpha losses and ripple diffusion losses to be greater than those from a comparable non-reversed magnetic shear plasma in the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. High central q is found to increase alpha ripple losses as well as first orbit losses of alphas in the reversed shear simulations. A simple rippl… more
Date: March 1, 1997
Creator: Redi, M. H.; White, R. B.; Batha, S. H.; Levinton, F. M. & McCune, D. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ion heating in the field-reversed configuration (FRC) by rotating magnetic fields (RMF) near cyclotron resonance

Description: The trajectories of ions confined in a Solovev FRC equilibrium magnetic geometry and heated with a small-amplitude, odd-parity rotating magnetic field, have been studied with a Hamiltonian computer code. When the RMF frequency is in the ion-cyclotron range, explosive heating occurs. Higher-energy ions are found to have betatron-type orbits, preferentially localized near the FRC midplane. These results are relevant to a compact magnetic-fusion-reactor design.
Date: July 20, 2000
Creator: Cohen, Samuel A. & Glasser, Alan H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Microstability theory for the field reversed configuration. Final report

Description: This report summarizes the work done in the last contract period. Previous work has been described in Annual Performance Reports. The work carried on under this Research Grant and not included in previous progress and annual reports includes two distinct items. One work is a study of the nonlocal high beta microstability of the FRC (Field Reversed Configuration), which they began sometime ago. This study identified the limiting beta (=4{pi}nT/B{sup 2}) for the mode to remain unstable. The study… more
Date: November 5, 1997
Creator: Krall, Nicholas A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Numerical study of tilt stability of prolate field-reversed configurations

Description: Global stability of the Field-Reversed Configuration (FRC) has been investigated numerically using both 3D MHD and hybrid (fluid electron and delta f particle ion) simulations. The stabilizing effects of velocity shear and large ion orbits on the n = 1 internal tilt mode in the prolate FRCs have been studied. Sheared rotation is found to reduce the growth rate, however a large rotation rate with Mach number of M greater than or approximately equal to 1 is required in order for significant reduc… more
Date: June 21, 2000
Creator: Belova, E. V.; Jardin, S. C.; H. Ji, M. Yamada & Kulsrud, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dynamo theory: can amplification of magnetic-field profiles arise from a cross-field alpha effect

Description: The answer to the title question is here provided in cylindrical geometry for an essentially arbitrary radial dependence of this alpha effect, except that it is subject to a simple, physically required constraint. The interest in this type of alpha effect derives from its connection with compressible turbulence, which is usually not considered in kinematic dynamo theory.
Date: April 1, 1982
Creator: Gerwin, Richard & Keinigs, Rhon
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Observations of separatrix motion during the formation of a field-reversed configuration

Description: An axial array of B/sub z/ probes is used to monitor the formation and initial motion of the x-point of the separatrix in a field-reversed configuration. The x-point is observed to form near the outside edge of the main coil at approximately 3.0 ..mu..s after main field initiation and then move rapidly toward the center of the coil.
Date: February 1, 1981
Creator: Cochrane, J.C.; Armstrong, W.T.; Lipson, J. & Tuszewski, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Excluded flux analysis of a field reversed plasma

Description: A simple eigenvalue approach for mapping the vacuum field between an assumed separatrix and a conducting wall is described. This allows an improved determination of the plasma shape in Field Reversed Experiments (FRX) compared to previous estimates based on excluded flux radius measurements. It is also shown that an array of magnetic field diagnostics located outside the discharge tube cannot resolve features of the plasma shape that have scale length smaller than about a coil radius.
Date: September 1, 1980
Creator: Tuszewski, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FRC studies on FRX-B

Description: Recent experimental studies of Field-Reversed Configurations (FRC) on the FRX-B device have included (1) characterization of FRC formation with regard to loss of bias flux, (2) examination of FRC equilibria through separatrix profiles, (3) formation of FRC's with different end-mirror configurations, and (4) extension of FRC parameter range. Studies on loss of bias flux during the pre-ionization (PI) phase of FRC formation are presented in another paper dedicated solely to PI considerations. Los… more
Date: January 1, 1980
Creator: Armstrong, W.T.; Cochrane, J.C.; Lipson, J.; Linford, R.K.; McKenna, K.F.; Sgro, A.G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Initial Ionization Stage of FRC Formation

Description: A Field-Reversed Configuration (FRC) is a prolate compact torus that is confined by poloidal fields only. Theta-pinch formation of an FRC employs an initial bias field, B/sub 1/, whose direction is opposite to that of the main theta-pinch field. Some fraction of the flux associated with this bias field eventually constitutes the closed-field-line flux of the FRC. Experimental and theoretical evidence suggest that the longest-lived FRC's are obtained when the closed flux is maximized. Because th… more
Date: January 1, 1980
Creator: Commisso, R. J.; Armstrong, W. T.; Cochrane, J. C.; Ekdahl, C. A.; Lipson, J.; Linford, R. K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Stability of field-reversed mirrors

Description: The stability of the field-reversed mirror configuration to acoustic modes in the low-frequency regime is analyzed. While previous work has been done using field-reversed configurations in the geometrical limit of infinite length, or zero plasma width, the attempt here is to analyze an equilibrium that has order unity aspect ratio. Further, while previous efforts have concentrated on fluid equilibrium or a specific distribution function, the approach here is to develop a formalism that can be u… more
Date: January 1, 1978
Creator: Morse, E. C. & Miley, G. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Studies of the Formation of Field Reversed Plasma by a Magnetized Co-Axial Plasma Gun

Description: The gun injects axially into a drift tank followed by a magnetic mirror. For the experiments reported here, only the guide coils outside the vacuum vessel and solenoids on the plasma gun electrodes were used; the mirror coil was not energized. A stainless steel flux conserver is placed in the mirror throat to prevent the plasma from contacting the nonconducting vacuum wall in the region of the mirror. An axis encircling array of magnetic loop probes includes four diamagnetic loops and a loop wh… more
Date: May 28, 1980
Creator: Turner, W. C.; Granneman, E. H. A.; Hartman, C. W.; Prono, D. S.; Taska, J. & Smith, A. C., Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Power-crowbar impacts on plasma characteristics in ZT-40

Description: Detailed analysis of the impact of I/sub phi/ and I/sub theta/ power crowbars on the ZT-40 plasma is presented for the operational period between shots 1620-3600. It is demonstrated that in both aided- and self-reversed modes the main effect of the I/sub phi/ power crowbar is to lengthen the time to l/e of peak current, whereas the main effect of the I/sub theta/ power crowbar is to extend the reversal of B/sub phi/ at the wall, primarily in self-reversed operation. It is shown that this extens… more
Date: July 1, 1981
Creator: Watt, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Observations of plasma tearing instabilities and associated axial translation in field-reversed experiments

Description: Tearing and reconnection processes during the formation and quiescent periods of a field-reversed configuration are studied with an axial array of compensated diamagnetic loops. Several representative plasma shots are documented.
Date: February 1, 1981
Creator: Armstrong, W.T.; Cochrane, J.C.; Lipson, J. & Tuszewski, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Hall current effects on tearing modes in rotating reverse field plasmas

Description: It has been experimentally observed for some time that certain tearing modes in plasmas may be suppressed if the plasma rotates in a preferred direction. In this paper we treat the m=0, finite wavelength tearing mode in cylindrical geometry for a reversed field plasma equilibrium and show that by generalizing Ohm's law to include Hall current terms, we are able to explain this effect of rotation on tearing modes. Our results agree qualitatively with earlier analysis and numerical simulations of… more
Date: March 1, 1980
Creator: Kappraff, Jay; Grossmann, William & Kress, Michael
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Beta II plasma-gun mechanical design and construction

Description: The magnetized coaxial plasma gun (located on the east end of the Beta II facility at the Lawrence Livermore Laboratory) will be used to test a new method of initiating a field reversed mirror plasma. The field-reversed mirror is expected to improve the mirror-fusion reactor by enhancing the ratio of fusion power to injected power. This paper concentrates on the mechanical design and construction of the magnetized coaxial plasma gun and also discusses the diagnostic devices necessary to demonst… more
Date: November 12, 1979
Creator: Pedrotti, Laurence; Deis, Gary; Wong, Robert; Calderon, Manuel; Chargin, Anthony & Garner, Donald
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Annual performance report for ``A program of FRC theory research``

Description: The original activities carried out under this Grant were specific to the Fusion scheme known as the Field Reversed Configuration (FRC). With the decisions of the Department of Energy to deemphasize experimental activity in the areas known as ``alternate concepts,`` we have generalized our studies. Since the research we have perfomed on the FRC led us into the area of high beta (8{pi}nT/B{sup 2}) and large orbits, we have chosen to emphasize those areas of plasma physics. The relevance to the m… more
Date: May 15, 1992
Creator: Krall, N. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computational methods for reversed-field equilibrium

Description: Investigating the temporal evolution of reversed-field equilibrium caused by transport processes requires the solution of the Grad-Shafranov equation and computation of field-line-averaged quantities. The technique for field-line averaging and the computation of the Grad-Shafranov equation are presented. Application of Green's function to specify the Grad-Shafranov equation boundary condition is discussed. Hill's vortex formulas used to verify certain computations are detailed. Use of computer … more
Date: April 15, 1980
Creator: Boyd, John K.; Auerbach, Steven P.; Willmann, Peter A.; Berk, Herbert L. & McNamara, Brendan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Computational methods for reversed-field equilibrium

Description: Investigating the temporal evolution of reversed-field equilibrium caused by transport processes requires the solution of the Grad-Shafranov equation and computation of field-line-averaged quantities. The technique for field-line averaging and the computation of the Grad-Shafranov equation are presented. Application of Green's function to specify the Grad-Shafranov equation boundary condition is discussed. Hill's vortex formulas used to verify certain computations are detailed. Use of computer … more
Date: April 15, 1980
Creator: Boyd, John K.; Auerbach, Steven P.; Willmann, Peter A.; Berk, Herbert L. & McNamara, Brendan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Reversed-field pinch fusion reactor

Description: A conceptual engineering design of a fusion reactor based on plasma confinement in a toroidal Reversed-Field Pinch (RFP) configuration is described. The plasma is ohmically ignited by toroidal plasma currents which also inherently provide the confining magnetic fields in a toroidal chamber having major and minor radii of 12.7 and 1.5 m, respectively. The DT plasma ignites in 2 to 3 s and undergoes a transient, unrefueled burn at 10 to 20 keV for approx. 20 s to give a DT burnup of approx. 50%. … more
Date: January 1, 1980
Creator: Hagenson, R. L. & Krakowski, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Conceptual physics design of a compact torus fusion reactor (CTOR)

Description: The general approach to fusion power embodied by field-reversed plasmoid configurations is reviewed within the context of a power reactor. A simple analytic formulation is developed and applied to the field-reversed theta pinch as a core plasma for a thermonuclear reactor. These calculations and results are based on a minimum power constraint and will serve as a basis for more exact and detailed reactor modeling.
Date: July 1, 1980
Creator: Hagenson, R. L. & Krakowski, R. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Evaluation of a relativistic electron ring system as a plasma target for buildup of compact-toroid configurations

Description: A review of the idea of using plasma-loaded electron rings as buildup targets for future compact-toroid machines is presented. Present experiments at Cornell University and Nagoya University are analyzed, and the need for auxiliary heating to reach interesting temperatures is described. Consideration of the effect of two-stream instability, toroidal field, and plasma containment are discussed.
Date: June 26, 1980
Creator: Condit, W.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen