257 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Aspect Ratio"  
Results: 1 - 24 next
open access

Multiple-gap theory of toroidal Alfven waves with kinetic effects

Description: The stability of kinetic toroidal Alfven waves with multi-gap coupling is analyzed by using the two-dimensional ballooning transform. An alternate convergence scheme, based on the smallness of the inverse aspect ratio, is devised. The resulting wave functions are oscillatory and do not balloon in contrast to the wave functions of conventional ballooning theory. It is shown that the single-gap theory is a special, weak shear (s {yields} 0) limit of the formalism. Analytical and numerical results… more
Date: September 1, 1992
Creator: Zhang, X. D.; Zhang, Y. Z. & Mahajan, S. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Comparative analysis of a fusion reactor blanket in cylindrical and toroidal geometry using Monte Carlo

Description: Differences in neutron fluxes and nuclear reaction rates in a noncircular fusion reactor blanket when analyzed in cylindrical and toroidal geometry are studied using Monte Carlo. The investigation consists of three phases--a one-dimensional calculation using a circular approximation to a hexagonal shaped blanket; a two-dimensional calculation of a hexagonal blanket in an infinite cylinder; and a three-dimensional calculation of the blanket in tori of aspect ratios 3 and 5. The total blanket rea… more
Date: March 1, 1976
Creator: Chapin, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ELMO Bumpy Torus Reactor (EBTR) reference design

Description: The goal of the ELMO Bumpy Torus Reactor (EBTR) study is the evaluation of the EBT confinement concept as the basis for development of a commercial fusion power reactor. A multidisciplinary, self-consistent treatment of EBT reactor scaling and design has been completed and a reference design (EBTR-48) has been developed. This design, based on a realistic plasma model and relatively conservative engineering parameters (i.e., 1 MW/m/sup 2/ neutron wall loading and a 7.3 T maximum toroidal field),… more
Date: November 1, 1976
Creator: McAlees, D. G.; Uckan, N. A. & Bettis, E. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Theoretical considerations of magnetic cusps for electron-beam fusion systems

Description: Single particle motion of relativistic electrons in cusp magnetic fields has been studied analytically and numerically to evaluate some aspects of this approach to beam transport and trapping in inertial confinement schemes. It is found that angular momentum is a serious problem, and that at least one mirror loss cone exists for any initial injection conditions. Specular and randomizing reflections are investigated. It is found that charge and current neutral injection into a cusp will not prov… more
Date: April 1, 1977
Creator: Wright, T. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

EPR and TNS. [Technological next step after an experimental power reactor]

Description: The recognition of the need for an intermediate CTR experiment, to be constructed before the first experimental power reactor (EPR) is discussed. This device, called the next step (TNS), is the logical successor of the Technology Test Assembly with Plasma (TTAP) concept. The TNS has derived its basic function from the TTAP; namely, operational testing of EPR-relevant technologies and plasma control techniques. The technical reasons which militate against the possibility of successful EPR constr… more
Date: June 1, 1976
Creator: Clarke, J. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Theory of continuum damping of toroidal Alfven Eigenmodes in finite-[beta] tokamaks

Description: We have formulated a general theoretical approach for analyzing two-dimensional structures of high-n Toroidal Alfven Eigenmodes (TAE) in large aspect-ratio, finite-[beta] tokamaks. Here, n is the toroidal wave number and [beta] is the ratio between plasma and magnetic pressures. The present approach generalizes the standard ballooning-mode formalism and is capable of treating eigenmodes with extended global radial structures as well as finite coupling between discrete and continuous spectra. Em… more
Date: May 1, 1993
Creator: Zonca, F. & Chen, Liu.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Moment equation approach to neoclassical transport theory

Description: The neoclassical cross-field fluxes for a toroidally confined, axisymmetric plasma are calculated in terms of the thermodynamic forces from the fluid continuity and momentum balance equations. This macroscopic formulation of neoclassical transport theory unifies the numerous complex expressions for the transport coefficients, previously obtained by solving the Fokker-Planck equation, and elucidates their physical basis. In the large aspect ratio limit, the continuous transition in the scaling o… more
Date: September 1, 1977
Creator: Hirshman, S. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

ITER plasma equilibrium and poloidal field system design

Description: Several poloidal field coil design issues are identified when assessing the benefits of high plasma elongaton in an ITER device. Among these are the sensitivity of PF ampere-turens and coil energy to specific constraints on the plasma shape and profiles and the optimal placement of PF coils subject to assumed operating scenarios. Two versons of free boundary equilibrium codes presently under development at the Oak Ridge National Laboratory (ORNL), HEQ and VEQ, are used to solve several PF desig… more
Date: January 1, 1988
Creator: Strickler, D. J.; Galambos, J. D. & Peng, Y. K. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Continuous tokamaks

Description: A tokamak configuration is proposed that permits the rapid replacement of a plasma discharge in a ''burn'' chamber by another one in a time scale much shorter than the elementary thermal time constant of the chamber first wall. With respect to the chamber, the effective duty cycle factor can thus be made arbitrarily close to unity minimizing the cyclic thermal stress in the first wall. At least one plasma discharge always exists in the new tokamak configuration, hence, a continuous tokamak. By … more
Date: April 1, 1978
Creator: Peng, Y. K. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Bootstrap dependence on plasma profile parameters

Description: The bootstrap fraction, I{sub bs}/I{sub p}, and the shape of the bootstrap current density, J{sub bs}(r), can depend sensitively on the shape of the plasma profiles. Beginning with Hirshman's form for the bootstrap current density, and making a large aspect ratio expansion (proceeding two orders in the square root of the inverse aspect ratio, {epsilon}), we derive an expression for the bootstrap fraction of the form I{sub bs}/I{sub p} = {epsilon}{sup {1/2}}{beta}{sub p}C{sub bs}({alpha}{sub n},… more
Date: August 1, 1992
Creator: Pomphrey, N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Manufacturing technology

Description: The mission of the Manufacturing Technology thrust area at Lawrence Livermore National Laboratory (LLNL) has been to have an adequate base of manufacturing technology, not necessarily resident at LLNL, to conduct their future business. The specific goals were (1) to develop an understanding of fundamental fabrication processes; (2) to construct general purpose process models that have wide applicability; (3) to document their findings and models in journals; (4) to transfer technology to LLNL p… more
Date: January 1, 1998
Creator: Blaedel, Kenneth L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Feasibility study of beam-beam compensation in the Tevatron with wires

Description: We explore the possibility of compensating long-range beam-beam interactions in the Tevatron by current carrying wires. Compensation strategies depend on whether the compensation is done close to the interaction or nonlocally, on the aspect ratio of the strong beam and on other details. Strategies for each case have been developed and applied to the Tevatron. We discuss the results of these strategies at injection and collision energy.
Date: May 1, 2005
Creator: Sen, Tanaji; /Fermilab; Erdelyi, Bela & U., /Northern Illinois
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

MHD stability properties of bean-shaped tokamaks

Description: A study of the MHD stability properties of bean-shaped tokamak plasmas is presented. For ballooning modes, while increased indentation gives larger ..beta.. stable configurations, the existence and accessibility of the second stable region is sensitive to the pressure and safety factor profiles. The second stable region appears at lower ..beta.. values for large aspect ratio and moderately high q-values. Finite-Larmor-radius (FLR) kinetic effects can significantly improve the stability properti… more
Date: March 1, 1984
Creator: Grimm, R. C.; Chance, M. S.; Todd, A. M. M.; Manickam, J.; Okabayashi, M.; Tang, W. M. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

OBSERVATION OF DIPOLAR FERROMAGNETISM BY TEM TECHNIQUES.

Description: Magnetostatic interactions play a central role in determining the magnetic response of an array of patterned magnetic elements or magnetized nanoparticles of given shape. The Fourier space approach recently introduced for the analytical computation of the demagnetizing tensor, field and energy for particles of arbitrary shape [1], has been recently extended to cover interactions between elements [2]. The main achievement has been the definition of a generalized dipole-dipole interaction for cyl… more
Date: August 1, 2004
Creator: BELEGGIA, M. ZHU,Y. TANDON,S. ET AL.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Multiple-gap theory of toroidal Alfven waves with kinetic effects

Description: The stability of kinetic toroidal Alfven waves with multi-gap coupling is analyzed by using the two-dimensional ballooning transform. An alternate convergence scheme, based on the smallness of the inverse aspect ratio, is devised. The resulting wave functions are oscillatory and do not balloon in contrast to the wave functions of conventional ballooning theory. It is shown that the single-gap theory is a special, weak shear (s {yields} 0) limit of the formalism. Analytical and numerical results… more
Date: September 1, 1992
Creator: Zhang, X. D.; Zhang, Y. Z. & Mahajan, S. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parametric analysis of the ARIES-III D-{sup 3}He tokamak reactor

Description: The multi-institutional ARIES study has completed a series of conceptual designs of tokamak fusion reactors that varies the assumed advances in technology and physics. The ARIES-III design uses a D- {sup 3}He fuel cycle and requires significant advances in physics to enhance economic attractiveness. The optimal design was characterized through systems analysis for eventual conceptual engineering design. Results from the systems analysis are summarized, and a comparison with the other ARIES desi… more
Date: August 1, 1993
Creator: Bathke, C. G.; Werley, K. A.; Miller, R. L.; Krakowski, R. A. & Santarius, J. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The role of plasma rotation on MHD instabilities in tokamaks

Description: An improved analysis of the linear stage of the internal kink mode has been developed to include plasma rotation and finite aspect ratio effects. The linear instabiliy growth rates are increased by the plasma rotation. A pseudo-variational, bilinear formalism is used to discretize the linear instability equations; Fourier decomposition is used in the periodic coordinate, and a mixed-finite element procedure is adopted in the radial direction. The numerical studies with the resulting PEST-like c… more
Date: June 1, 1993
Creator: Varadarajan, V. & Miley, G. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Bootstrap dependence on plasma profile parameters

Description: The bootstrap fraction, I{sub bs}/I{sub p}, and the shape of the bootstrap current density, J{sub bs}(r), can depend sensitively on the shape of the plasma profiles. Beginning with Hirshman`s form for the bootstrap current density, and making a large aspect ratio expansion (proceeding two orders in the square root of the inverse aspect ratio, {epsilon}), we derive an expression for the bootstrap fraction of the form I{sub bs}/I{sub p} = {epsilon}{sup {1/2}}{beta}{sub p}C{sub bs}({alpha}{sub n},… more
Date: August 1, 1992
Creator: Pomphrey, N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Formation and sustainment of a very low aspect ratio tokamak using coaxial helicity injection (the Helicity Injected Torus [HIT] experiment). Progress report No. 2, February 1, 1991--January 31, 1992

Description: In the paper we will detail the progress of the HIT experiment construction, including the following components: preliminary data and interpretation; diagnostic systems; vacuum vessel and pumping system; helicity source and power supplies; toroidal field coil and power supply; data acquisition system; collaboration with general atomics, with a brief summary given on each.
Date: June 1, 1992
Creator: Jarboe, T. R. & Nelson, B. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of a poloidal electric field on neoclassical transport in a multispecies tokamak plasma

Description: The effects of a poloidal potential variation of or der c{var_epsilon}, heating or neutral beam injection, upon neoclassical particle transport and plasma current are studied theoretically, for a realistic tokamak plasma with significant impurity content. Using an approximate collision operator, an analytic procedure is employed to calculate the transport coefficients in the low collisionality regime for a large aspect ratio tokamak. In the presence of carbon impurity, the ion diffusion coeffic… more
Date: December 1, 1992
Creator: Indireshkumar, K. & Stacey, W. M. Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The effects of plasma deformability on the feedback stabilization of axisymmetric modes in tokamak plasmas

Description: The effects of plasma deformability on the feedback stabilization of axisymmetric modes of tokamak plasmas are studied. It is seen that plasmas with strongly shaped cross sections have unstable motion different from a rigid shift. Furthermore, the placement of passive conductors is shown to modify the non-rigid components of the eigenfunction in a way that reduces the stabilizing eddy currents in these conductors. Passive feedback results using several equilibria of varying shape are presented.… more
Date: January 1, 1992
Creator: Ward, D. J. & Jardin, S. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Flow shear induced fluctuation suppression in finite aspect ratio shaped tokamak plasma

Description: The suppression of turbulence by the E {times} B flow shear and parallel flow shear is studied in an arbitrary shape finite aspect ratio tokamak plasma using the two point nonlinear analysis previously utilized in a high aspect rat& tokamak plasma. The result shows that only the E {times} B flow shear is responsible for the suppression of flute-like fluctuations. This suppression occurs regardless of the plasma rotation direction and is therefore, relevant for the VH mode plasma core as well as… more
Date: January 1, 1995
Creator: Hahm, T. S. & Burrell, K. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Existence of core localized toroidicity-induced Alfven eigenmode

Description: The core-localized toroidicity-induced Alfven eigenmode (TAE) is shown to exist at finite plasma pressure due to finite aspect ratio effects in tokamak plasma. The new critical beta for the existence of the TAE mode is given by {alpha}{approx} 3{epsilon} + 2s{sup 2}, where {epsilon} = r/R is the inverse aspect ratio, s is the magnetic shear and {alpha} = -Rq{sup 2}d{beta}/dr is the normalized pressure gradient. In contrast, previous critical {alpha} is given by {alpha} {approx} s{sup 2}. In the… more
Date: February 1, 1995
Creator: Fu, G. Y.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen