Quantifying fusion born ion populations in magnetically confined plasmas using ion cyclotron emission

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity $P_{ICE}$ scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, $n_\alpha/n_i$, of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha-particle confinement and stability in MCF plasmas. It confirms the magnetoacoustic cyclotron instability (MCI) as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas

Thermal analysis of the southern Powder River Basin, Wyoming

Journal ArticleTemperature and geologic data from over 3000 oil and gas wells within a 180 km x 30 km area that transect across the southern Powder River Basin in Wyoming, U.S.A., were used to determine the present thermal regime of the basin. Three-dimensional temperature fields within the transect, based on corrected bottom-hole temperatures (BHTs) and other geologic information, were assessed using: (1) A laterally constant temperature gradient model in conjunction with an L1 norm inversion method, and (2) a laterally variable temperature gradient model in conjunction with a stochastic inversion technique

A sandpile model with tokamak-like enhanced confinement phenomenology

Confinement phenomenology characteristic of magnetically confined plasmas emerges naturally from a simple sandpile algorithm when the parameter controlling redistribution scalelength is varied. Close analogues are found for enhanced confinement, edge pedestals, and edge localised modes (ELMs), and for the qualitative correlations between them. These results suggest that tokamak observations of avalanching transport are deeply linked to the existence of enhanced confinement and ELMs.Comment: Manuscript is revtex (latex) 1 file, 7 postscript figures Revised version is final version accepted for publication in PRL Revisions are mino

Bose-Einstein Correlations for Three-Dimensionally Expanding, Cylindrically Symmetric, Finite Systems

The parameters of the Bose-Einstein correlation function may obey an {\it $M_t$-scaling}, as observed in $S + Pb$ and $Pb + Pb$ reactions at CERN SPS. This $M_t$-scaling implies that the Bose-Einstein correlation functions view only a small part of the big and expanding system. The full sizes of the expanding system at the last interaction are shown to be measurable with the help the invariant momentum distribution of the emitted particles. A vanishing duration parameter can also be generated in the considered model-class with a specific $M_t$ dependence.Comment: 35 pages, ReVTeX, LaTeX, no figures, discussion extende

Self-consistent nonlinear kinetic simulations of the anomalous Doppler instability of suprathermal electrons in plasmas

Suprathermal tails in the distributions of electron velocities parallel to the magnetic field are found in many areas of plasma physics, from magnetic confinement fusion to solar system plasmas. Parallel electron kinetic energy can be transferred into plasma waves and perpendicular gyration energy of particles through the anomalous Doppler instability (ADI), provided that energetic electrons with parallel velocities v ≥ (ω + Ωce )/k are present; here Ωce denotes electron cyclotron frequency, ω the wave angular frequency and k the component of wavenumber parallel to the magnetic field. This phenomenon is widely observed in tokamak plasmas. Here we present the first fully self-consistent relativistic particle-in-cell simulations of the ADI, spanning the linear and nonlinear regimes of the ADI. We test the robustness of the analytical theory in the linear regime and follow the ADI through to the steady state. By directly evaluating the parallel and perpendicular dynamical contributions to j · E in the simulations, we follow the energy transfer between the excited waves and the bulk and tail electron populations for the first time. We find that the ratio Ωce /(ωpe + Ωce ) of energy transfer between parallel and perpendicular, obtained from linear analysis, does not apply when damping is fully included, when we find it to be ωpe /(ωpe + Ωce ); here ωpe denotes the electron plasma frequency. We also find that the ADI can arise beyond the previously expected range of plasma parameters, in particular when Ωce > ωpe . The simulations also exhibit a spectral feature which may correspond to observations of suprathermal narrowband emission at ωpe detected from low density tokamak plasmas

Continuous product innovation : a comparison of key elements across different contingency sets

This paper discusses results from an international study of continuous improvement in product innovation. The empirical research is based upon a theoretical model of continuous product innovation (CPI) that identifies contingencies, behaviours, levers and performances relevant to improving product innovation processes. As successful knowledge management is widely recognised as a key capability for firms to successfully develop CPI, companies have been classified according to identified contingencies and the impact of these contingencies on key knowledge management criteria. Comparative analysis of the identified groups of companies has demonstrated important differences between the learning behaviours found present in the two groups thus identified, and in the levers used to develop and support these behaviours. The selection of performance measures by the two groups has highlighted further significant differences in the way the two groups understand and measure their CPI processes. Finally, the paper includes a discussion of appropriate mechanisms for firms with similar contingency sets to improve their approaches to organisational learning and product innovation

An Analysis of the Strayton Engine, a Brayton and Stirling Cycle Recuperating Engine

This paper explores the novel Strayton engine concept. This engine combines the cycles of a Brayton engine with that of a Stirling engine to create a highly efficient recuperating gas turbine engine. In the explored case, both Brayton cycle and Stirling cycle engines are used to generate electrical power. Additionally, the Stirling engine is used to draw heat out of the Brayton turbine (acting to cool the turbine blades), while also pumping heat into Brayton cycle just before combustion occurs (acting as the mechanism for recuperation). The purpose of this paper is to detail the system level modeling techniques used to generate the simulation, perform a cycle analysis of the combined cycle engine, identify key technologies and challenges associated with the concept, and compare potential performance gains with existing gas turbine engines and internal combustion engines. Topics such as controls, blade cooling effects, engine weight, and heat transfer using heat pipe are also explored. Results from this work show potential architectures that could provide the required heat transfer rates, potential control strategies, and performance benefits, including efficiency gains between 10% and 3% on engines ranging from 200HP to 670HP with the combined cycle engine

Realistic Expanding Source Model for Invariant One-Particle Multiplicity Distributions and Two-Particle Correlations in Relativistic Heavy-Ion Collisions

We present a realistic expanding source model with nine parameters that are necessary and sufficient to describe the main physics occuring during hydrodynamical freezeout of the excited hadronic matter produced in relativistic heavy-ion collisions. As a first test of the model, we compare it to data from central Si + Au collisions at p_lab/A = 14.6 GeV/c measured in experiment E-802 at the AGS. An overall chi-square per degree of freedom of 1.055 is achieved for a fit to 1416 data points involving invariant pi^+, pi^-, K^+, and K^- one-particle multiplicity distributions and pi^+ and K^+ two-particle correlations. The 99-percent-confidence region of parameter space is identified, leading to one-dimensional error estimates on the nine fitted parameters and other calculated physical quantities. Three of the most important results are the freezeout temperature, longitudinal proper time, and baryon density along the symmetry axis. For these we find values of 92.9 +/- 4.4 MeV, 8.2 +/- 2.2 fm/c, and 0.0222 + 0.0096 / - 0.0069 fm^-3, respectively.Comment: 37 pages and 12 figures. RevTeX 3.0. Submitted to Physical Review C. Complete preprint, including device-independent (dvi), PostScript, and LaTeX versions of the text, plus PostScript files of all figures, are available at http://t2.lanl.gov/publications/publications.html or at ftp://t2.lanl.gov/publications/res