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Computational Support for Alternative Confinement Concepts Basic Plasma Science

Description: This is the final report for contract DE-FG03-99ER54528, ''Computational Support for Alternative Confinement Concepts''. Progress was made in the following areas of investigation: (1) Extensive studies of the confinement properties of conventional Reversed-field Pinch (RFP) configurations (i.e., without current profile control) were performed in collaboration with the Royal Institute of Technology (KTH) in Stockholm, Sweden. These studies were carried out using the full 3-dimensional, finite-{b… more
Date: December 9, 2002
Creator: Schnack, Dalton D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The Effect of Turbulent Stresses on the Experimental Determination of a Thermal Diffusivity Due to Turbulent Transport

Description: In plasmas where the transport processes are dominated by turbulence, it is not always straightforward to identify the magnitude of the experimental transport diffusion coefficients. This is primarily due to the fact that with turbulent transport, the separation of the convective and conductive terms depends upon the type of turbulence and/or the model which is used to describe it. For the energy transport it is not just a matter of deciding whether the convection term is 5/2 or 3/2 times the p… more
Date: July 1, 2002
Creator: Baker, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Free-boundary Full-pressure Island Healing in a Stellarator: Coil-healing

Description: The lack of axisymmetry in stellarators guarantees that in general magnetic islands and chaotic magnetic field lines will exist. As particle transport is strongly tied to the magnetic field lines, magnetic islands and chaotic field lines result in poor plasma confinement. For stellarators to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux-surfaces, and the suppression of magnetic islands is a critical is… more
Date: May 7, 2002
Creator: S.R.Hudson; Reiman, A.; Strickler, D.; Brooks, A.; Monticello, D.A. & Hirshman, and S.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Results of NSTX Heating Experiments

Description: The National Spherical Torus Experiment (NSTX) at Princeton is designed to assess the potential of the low-aspect-ratio spherical torus concept for magnetic plasma confinement. The plasma has been heated by up to 5 MW of neutral beam injection, NBI, at an injection energy of 90 keV and up to 6 MW of high harmonic fast wave, HHFW, at 30 MHz. NSTX has achieved beta T of 32%. A variety of MHD phenomena have been observed to limit eta. NSTX has now begun addressing E scaling, eta limits and current… more
Date: June 18, 2002
Creator: Mueller, D.; Ono, M.; Bell, M. G.; Bell, R. E.; Bitter, M.; Bourdelle, C. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Scrape-Off Layer Features of the QH-Mode

Description: The quiescent high confinement (QH-mode) and quiescent double barrier (QDB) modes in DIII-D have long-duration H-mode confinement without ELMs, possibly an alternative operating mode in future tokamaks for avoiding damage by ELMS. Instead of ELMs, there is an edge harmonic oscillation (EHO), which is a continuous electromagnetic mode with associated density fluctuations. The edge pedestal is similar to ELMing H-mode, but at very low density to daw. We see C{sup +6} ion temperatures of 3-7 keV i… more
Date: May 23, 2002
Creator: Lasnier, C. J.; Burrell, K. H.; deGrassie, J. S.; Leonard, A. W.; Moyer, R. A.; Porter, G. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Comparison of Carbon and Main Ion Radiation Profiles in Matched Helium and Deuterium Plasmas in JET

Description: This paper examines the radiation profiles and corresponding ionization source profiles of various carbon and main plasma ions in matched helium and deuterium L-mode plasmas in JET. Operation in helium should reduce chemical sputtering of carbon substantially compared with deuterium. The radiation intensities from C{sup 1+}, C{sup 2+} and C{sup 3+} in the helium plasmas showed reduction by factors of 8, 10 and 25 respectively along the inner SOL and divertor leg compared with the deuterium case… more
Date: May 17, 2002
Creator: Fenstermacher, M. E.; Lawson, K. D.; Porter, G. D.; Erents, S. K.; Ingesson, C.; Mathews, G. F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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EXPLICT CALULATIONS OF HOMOCLINIC TANGLES SURROUNDING MAGNETIC ISLANDS IN TOKAMAKS

Description: We present explicit calculations of the complicated geometric objects known as homoclinic tangles that surround magnetic islands in the Poincare mapping of a tokamak's magnetic field. These tangles are shown to exist generically in the magnetic field of all toroidal confinement systems. The geometry of these tangles provides an explanation for the stochasticity known to occur near the X-points of the Poincare mapping. Furthermore, the intersection of homoclinic tangles from different resonances… more
Date: June 1, 2002
Creator: Roeder, R. K. W.; Rapoport, B. I. & Evans, T. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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About the Toroidal Magnetic Field of a Tokamak Burning Plasma Experiment with Superconducting Coils

Description: In tokamaks, the strong dependence on the toroidal magnetic field of both plasma pressure and energy confinement is what makes possible the construction of small and relatively inexpensive burning plasma experiments using high-field resistive coils. On the other hand, the toroidal magnetic field of tokamaks using superconducting coils is limited by the critical field of superconductivity. In this article, we examine the relative merit of raising the magnetic field of a tokamak plasma by increas… more
Date: February 20, 2002
Creator: Mazzucato, E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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