Download or read book Turbulent Transport of Energetic Ions and Thermal Plasmas written by Shu Zhou and published by . This book was released on 2011 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three experiments are conducted to study the effect of the turbulent waves on the transport of fast ions and thermal plasmas. In the first experiment, strong drift wave turbulence with linear geometry is observed in the Large Plasma Device (LAPD) on density gradients produced by a plate limiter. Energetic lithium ions orbit through the turbulent region. Scans with a collimated ion analyzer and with Langmuir probes give detailed profiles of the fast ion spatial distribution and the fluctuating fields. The fast-ion transport decreases rapidly with increasing fast-ion gyroradius. Unlike the diffusive transport caused by Coulomb collisions, in this case the turbulent transport is super-diffusive. Analysis and simulation suggest that such super-diffusive transport is due to the interaction of the fast ions with the low-frequency two-dimensional electrostatic turbulence. The second experiment studies the dependence of the fast ion transport on the nature of the turbulent waves. Strong turbulent waves with cylindrical geometry are observed in the LAPD on density gradients produced by an annular obstacle. The characteristics of the fluctuations are modified by changing the plasma species from helium to neon, and by modifying the bias on the obstacle. Different spatial structure sizes and correlation lengths (Lcorr) of the wave potential fields alter the fast ion transport. The effects of electrostatic fluctuations are reduced due to gyro-averaging, which explains the difference in the fast-ion transport. A transition from super-diffusive to sub-diffusive transport is observed when the fast ion interacts with the waves for most of a wave period, which agrees with theoretical predictions. The transport of thermal plasmas under electrostatic waves is explored in the third experiment. Sheared azimuthal flow is driven at the edge of a magnetized plasma cylinder through edge biasing. Strong fluctuations of density and potential are observed at the plasma edge, accompanied by large density gradient. Edge turbulence and cross-field transport are modified by changing the bias voltage on the obstacle and the axial magnetic field strength. In cases with low V bias and large Bz, improved plasma confinement is observed, along with steeper edge density gradients. The radially sheared flow induced by E x B dramatically changes the cross-phase between density and potential fluctuations, which causes the wave-induced particle flux to reverse its direction across the shear layer and forms a transport barrier. In cases with higher bias voltage or smaller Bz large radial transport and rapid depletion of the central plasma density are observed. Two-dimensional cross-correlation measurement shows that a mode with azimuthal mode number m=1 and large radial correlation length dominates the outward transport in these cases. Linear analysis based on a two-fluid Braginskii model suggests that the fluctuations are driven by both density gradient and flow shear at the plasma edge.
Download or read book Turbulent Transport In Magnetized Plasmas Second Edition written by C Wendell Horton, Jr and published by #N/A. This book was released on 2017-07-21 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a few seconds with large machines, scientists and engineers have now created the fusion power of the stars in the laboratory and at the same time find the rich range of complex turbulent electromagnetic waves that transport the plasma confinement systems. The turbulent transport mechanisms created in the laboratory are explained in detail in the second edition of 'Turbulent Transport in Magnetized Plasmas' by Professor Horton.The principles and properties of the major plasma confinement machines are explored with basic physics to the extent currently understood. For the observational laws that are not understood — the empirical confinement laws — offering challenges to the next generation of plasma students and researchers — are explained in detail. An example, is the confinement regime — called the 'I-mode' — currently a hot topic — is explored.Numerous important problems and puzzles for the next generation of plasma scientists are explained. There is growing demand for new simulation codes utilizing the massively parallel computers with MPI and GPU methods. When the 20 billion dollar ITER machine is tested in the 2020ies, new theories and faster/smarter computer simulations running in near real-time control systems will be used to control the burning hydrogen plasmas.
Download or read book The Transport of Energetic and Thermal Particles in Strongly Turbulent Plasma written by Silvia Valeria Annibaldi and published by . This book was released on 2001 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Transfer and Dissipation in Plasma Turbulence written by Yan Yang and published by Springer. This book was released on 2019-05-02 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book revisits the long-standing puzzle of cross-scale energy transfer and dissipation in plasma turbulence and introduces new perspectives based on both magnetohydrodynamic (MHD) and Vlasov models. The classical energy cascade scenario is key in explaining the heating of corona and solar wind. By employing a high-resolution hybrid (compact finite difference & WENO) scheme, the book studies the features of compressible MHD cascade in detail, for example, in order to approximate a real plasma cascade as “Kolmogorov-like” and to understand features that go beyond the usual simplified theories based on incompressible models. When approaching kinetic scales where plasma effects must be considered, it uses an elementary analysis of the Vlasov–Maxwell equations to help identify the channels through which energy transfer must be dissipated. In addition, it shows that the pressure–strain interaction is of great significance in producing internal energy. This analysis, in contrast to many other recent studies, does not make assumptions about wave-modes, instability or other specific mechanisms responsible for the dynamics – the results are direct consequences of the Vlasov–Maxwell system of equations. This is an important step toward understanding dissipation in turbulent collisionless plasma in space and astrophysics.
Download or read book Lecture Series on Turbulent Transport in Tokamaks written by Ronald E. Waltz and published by . This book was released on 1987 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steady State Turbulent Transport in Magnetic Fusion Plasmas written by and published by . This book was released on 2007 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: For more than a decade, the study of microturbulence, driven by ion temperature gradient (ITG) drift instabilities in tokamak devices, has been an active area of research in magnetic fusion science for both experimentalists and theorists alike. One of the important impetus for this avenue of research was the discovery of the radial streamers associated the ITG modes in the early nineties using a Particle-In-Cell (PIC) code. Since then, ITG simulations based on the codes with increasing realism have become possible with the dramatic increase in computing power. The notable examples were the demonstration of the importance of nonlinearly generated zonal flows in regulating ion thermal transport and the transition from Bohm to GyroBoham scaling with increased device size. In this paper, we will describe another interesting nonlinear physical process associated with the parallel acceleration of the ions, that is found to play an important role for the steady state turbulent transport. Its discovery is again through the use of the modern massively parallel supercomputers.
Download or read book US Japan Workshop on ION Temperature Gradient Turbulent Transport written by Claude Wendell Horton and published by American Institute of Physics. This book was released on 1994 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the papers from a conference, the purpose of which was to advance the understanding of the transport of heat across magnetic fields in high temperature plasmas by presenting the latest theoretical, computational and experimental results for ion temperature gradient driven transport.
Download or read book Momentum Transport Radial Electric Field and Ion Thermal Energy Confinement in Very High Temperature Plasmas written by Darin Richard Ernst and published by . This book was released on 1998 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Transport in Rotating Tokamak Plasmas written by Francis James Casson and published by . This book was released on 2011 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Ion Transport Phenomena in Turbulent Toroidal Plasmas written by Fabian Manke and published by . This book was released on 2020 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: : Plasma physics ; statistics ; turbulence ; suprathermal ions ; non-diffusive transport ; intermittency ; particle beam ; fractional diffusion ; truncation effects ; tempered stable random processes.
Download or read book Turbulent Transport in Magnetized Plasmas written by C. Wendell Horton Jr and published by World Scientific Publishing Company. This book was released on 2017-06-02 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a few seconds with large machines, scientists and engineers have now created the fusion power of the stars in the laboratory and at the same time find the rich range of complex turbulent electromagnetic waves that transport the plasma confinement systems. The turbulent transport mechanisms created in the laboratory are explained in detail in the second edition of 'Turbulent Transport in Magnetized Plasmas' by Professor Horton.The principles and properties of the major plasma confinement machines are explored with basic physics to the extent currently understood. For the observational laws that are not understood -- the empirical confinement laws -- offering challenges to the next generation of plasma students and researchers -- are explained in detail. An example, is the confinement regime -- called the 'I-mode' -- currently a hot topic -- is explored.Numerous important problems and puzzles for the next generation of plasma scientists are explained. There is growing demand for new simulation codes utilizing the massively parallel computers with MPI and GPU methods. When the 20 billion dollar ITER machine is tested in the 2020ies, new theories and faster/smarter computer simulations running in near real-time control systems will be used to control the burning hydrogen plasmas.
Download or read book Transport of Energetic Particles in Turbulent Plasmas written by Thilo Hauff and published by . This book was released on 2009 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport Phenomena in Partially Ionized Plasma written by V.A. Rozhansky and published by CRC Press. This book was released on 2001-11-22 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport phenomena in plasmas are the relatively slow processes of particle momentum and energy transport systems in a state of mechanical equilibrium. In contrast to neutral gases, these phenomena in plasmas are greatly influenced by self-consistent fields, in particular electric fields. These can produce particle and energy fluxes, in addition to those generated by the inhomogeneity of the plasma composition and temperature. As a result, the physical effects accompanying transport phenomena in plasmas are far more numerous and complicated than those in neutral gases, and the solution of corresponding problems is more difficult. The effects, however, are usually far more interesting and sometimes surprising. This book presents a systematic survey and analysis of the main mechanisms of transport phenomena in plasma and gives examples of gradually increasing complexity to illustrate these mechanisms and the relationships between them. The author pays special attention to the analysis of experimental measurements and considers the relevant processes analytically as well as qualitatively. The majority of problems dealt with in this book are of considerable practical interest, and the phenomena described often determine the main characteristics of processes and devices. Transport Phenomena in Partially Ionized Plasma will be of interest to researchers who need to know the properties of real, specific systems, as well as to engineers and advanced students in the physics of plasmas, semiconductors, various types of gas discharges and the ionosphere.
Download or read book Turbulent Particle Transport in H Mode Plasmas on Diii D written by Xin Wang and published by . This book was released on 2016 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle transport is an important topic in plasma physics. It determines the density profile of a burning plasma within a tokamak a magnetic confinement device. Microscopic turbulent particle transport is two orders of magnitude larger than other transport mechanisms for electrons and small ions. In order to confine a plasma in a tokamak with a core density that exceeds the fusion criteria, it is essential to study turbulent particle transport. This thesis investigates how different plasma parameters such as the toroidal rotation and microscopic instabilities affect turbulent particle transport in the DIII-D tokamak. First, we show how toroidal rotation can indirectly affect particle transport, through its contribution to the radial electric field and thus the E B shearing rate. The plasma discharge which has best confinement is the one whose E B shearing rate is larger than or at least similar to the growth rates that drive turbulent transport at the plasma edge. Second, for the first time on DIII-D, we observe a correlation between electron density gradient and instability mode frequency in the plasma core. We find that, when the turbulence is driven by the ion temperature gradient (ITG), the local density gradient increases as the the absolute frequency of the dominant unstable mode decreases. Once the dominant unstable mode switches over to the trapped electron mode (TEM) regime, the local density gradient decreases again. As a result the density gradient reaches a maximum when the mode has zero frequency, which is corresponds to the cross over from ITG to TEM. This correlation opens a new opportunity for future large burning plasma devices such as ITER to increase the core density by controlling the turbulence regime. Finally, we show that, in low density regime, a reduction in core density is observed when electron cyclotron heating (ECH) is applied. This reduction is not the result of a change in turbulence regime nor the result of a change in the density gradient in the core. Through detailed time-dependent experimental analysis, linear gyro-kinetic simulations, and comparison to turbulence measurements we show that this reduction in core density is the result of an increase in turbulence drive at the plasma edge.
Download or read book Solar Energetic Particles written by Donald V. Reames and published by Springer. This book was released on 2017-03-10 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This concise primer introduces the non-specialist reader to the physics of solar energetic particles (SEP) and systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. More specifically, the timing of the onsets, the longitude distributions, the high-energy spectral shapes, the correlations with other solar phenomena (e.g. coronal mass ejections), as well as the all-important elemental and isotopic abundances of SEPs are investigated. Impulsive SEP events are related to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is the evidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a new technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated. Last but not least the role of SEP events as a radiation hazard in space is mentioned and a short discussion of the nature of the main particle telescope designs that have contributed to most of the SEP measurements is given.
Download or read book Transport Chaos And Plasma Physics 2 written by Benkadda Sadruddin and published by World Scientific. This book was released on 1996-08-22 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the early developments of 'nonlinear science', plasma physics played a major role in its evolution: solitons, hamiltonian chaos, distinction between absolute and convective instabilities, and dynamics of coherent structures in turbulence. Understanding transport in plasmas is important for fusion devices but also for fundamental astrophysics, for fluid mechanics, for theoretical chemistry and engineering, and plasma processing in engineering.This second workshop gathered experts in plasma physics, nonlinear phenomena and mathematics. It aimed at enabling theoreticians, numericians and experimentalists in plasma turbulence to relate electromagnetic fluctuations, modes of self-organisation and transport processes. It may lead to developing new diagnostics and new methods for signal processing.
Download or read book Transport of Energetic Ions During Relaxation Oscillations in Plasmas of Spherical Tori written by Ya. I. Kolesnichenko and published by . This book was released on 2001 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
