Download or read book 3D Fluid Simulations of Tokamak Edge Turbulence written by and published by . This book was released on 1995 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global 3D Two fluid Simulations of Turbulent Transport at Tokamak Edge Region written by Ben Zhu and published by . This book was released on 2017 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new global 3D two-fluid code, GDB, based on the drift-reduced Braginskii model has been developed and tested to study the turbulent transport across the entire tokamak edge region: from plasma sources in the inner core to plasma sinks in the outer-most scrape-off layer (SOL). In this code, profiles of plasma density, electron and ion temperature, electric potential, magnetic flux and parallel flow are evolved self-consistently. Milliseconds-long simulations are carried out in a shifted-circle magnetic configuration with realistic Alcator C-Mod tokamak inner wall limited (IWL) discharge parameters. The resistive ballooning instability is identified as the predominant driver of edge turbulence in the L-mode regime. Simulations show, in agreement with experimental observations, as the simulation moves towards density limit regime by increasing density, the turbulent transport is drastically enhanced and the plasma profiles are relaxed; on the other hand, as the simulation approaches to the H-mode regime by increasing temperature, the turbulent transport is suppressed and plasma profiles are steepened with a pedestal-like structure forming just inside of the separatrix. Radial transport level and turbulence statistics of these simulations also qualitatively match the experimental measurements. Spontaneous E x B rotation in the electron diamagnetic drift direction in the closed flux region are observed in all cases. It can be explained based on the steady state ion continuity relation [mathematical equation]. E x B rotation in the closed flux region is found mostly cancels the ion diamagnetic drift as H-mode-like regimes are approached, and exceeds it by a factor of two or more at lower temperatures due to parallel ion flows.
Download or read book Washington Journal written by and published by . This book was released on with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Journal of a trip to a GAR encampment in Washington, DC. Very detailed description of his trip to the White House. Includes description of a day spent sight seeing in Cleveland, OH on the return trip to Michigan.
Download or read book Blob Dynamics in 3D BOUT Simulations of Tokamak Edge Turbulence written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Propagating filaments of enhanced plasma density, or blobs, observed in 3D numerical simulations of a diverted, neutral-fueled tokamak are studied. Fluctuations of vorticity, electrical potential [phi], temperature T{sub e} and current density J{sub {parallel}} associated with the blobs have a dipole structure perpendicular to the magnetic field and propagate radially with large E · B drift velocities (> 1 km/s). The simulation results are consistent with a 3D blob dynamics model that incorporates increased parallel plasma resistivity (from neutral cooling of the X-point region), blob disconnection from the divertor sheath, X-point closure of the current loops, and collisional physics to sustain the [phi], T{sub e}, J{sub {parallel}} dipoles.
Download or read book Simulation of Turbulence in the Divertor Region of Tokamak Edge Plasma written by and published by . This book was released on 2004 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented for turbulence simulations with the fluid edge turbulence code BOUT [1]. The present study is focused on turbulence in the divertor leg region and on the role of the X-point in the structure of turbulence. Results of the present calculations indicate that the ballooning effects are important for the divertor fluctuations. The X-point shear leads to weak correlation of turbulence across the X-point regions, in particular for large toroidal wavenumber. For the saturated amplitudes of the divertor region turbulence it is found that amplitudes of density fluctuations are roughly proportional to the local density of the background plasma. The amplitudes of electron temperature and electric potential fluctuations are roughly proportional to the local electron temperature of the background plasma.
Download or read book Boundary Plasma Turbulence Simulations for Tokamaks written by and published by . This book was released on 2008 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.
Download or read book BOUT Simulations of Edge Turbulence in the DIII D Tokamak written by and published by . This book was released on 2012 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Plasma Fluxes to Material Surfaces with Self Consistent Edge Turbulence and Transport for Tokamaks written by and published by . This book was released on 2004 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The edge-plasma profiles and fluxes to the divertor and walls of a divertor tokamak with a magnetic X-point are simulated by coupling a 2D transport code (UEDGE) and a 3D turbulence code (BOUT). An relaxed iterative coupling scheme is used where each code is run on its characteristic time scale, resulting in a statistical steady state. Plasma variables of density, parallel velocity, and separate ion and electron temperatures are included, together with a fluid neutral model for recycling neutrals at material surfaces. Results for the DIII-D tokamak parameters show that the turbulence is preferentially excited in the outer radial region of the edge where magnetic curvature is destabilizing and that substantial plasma particle flux is transported to the main chamber walls. These results are qualitatively consistent with some experimental observations. The coupled transport/turbulence simulation technique provides a strategy to understanding edge-plasma physics in more detailed than previously available and to significantly enhance the realism of predictions of the performance of future devices.
Download or read book Simulation of Plasma Fluxes to Material Surfaces with Self consistent Edge Turbulence and Transport for Tokamaks written by R. Cohen and published by . This book was released on 2004 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The edge-plasma profiles and fluxes to the divertor and walls of a divertor tokamak with a magnetic X-point are simulated by coupling a 2D transport code (UEDGE) and a 3D turbulence code (BOUT). An relaxed iterative coupling scheme is used where each code is run on its characteristic time scale, resulting in a statistical steady state. Plasma variables of density, parallel velocity, and separate ion and electron temperatures are included, together with a fluid neutral model for recycling neutrals at material surfaces. Results for the DIII-D tokamak parameters show that the turbulence is preferentially excited in the outer radial region of the edge where magnetic curvature is destabilizing and that substantial plasma particle flux is transported to the main chamber walls. These results are qualitatively consistent with some experimental observations. The coupled transport/turbulence simulation technique provides a strategy to understanding edge-plasma physics in more detailed than previously available and to significantly enhance the realism of predictions of the performance of future devices.
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 Numerical Tokamak Turbulence Project written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary research objective of the Numerical Tokamak Turbulence Project (NTTP) is to develop a predictive ability in modeling turbulent transport due to drift-type instabilities in the core of tokamak fusion experiments, through the use of three-dimensional kinetic and fluid simulations and the derivation of reduced models.
Download or read book Numerical Tokamak Turbulence Project OFES Grand Challenge written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary research objective of the Numerical Tokamak Turbulence Project (NTTP) is to develop a predictive ability in modeling turbulent transport due to drift-type instabilities in the core of tokamak fusion experiments, through the use of three-dimensional kinetic and fluid simulations and the derivation of reduced models.
Download or read book Knyhy No 1 11 1568 1598 rr written by and published by . This book was released on 1959 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collisional Transport in Magnetized Plasmas written by Per Helander and published by Cambridge University Press. This book was released on 2005-10-06 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: A graduate level text treating transport theory, an essential element of theoretical plasma physics.
Download or read book 3D Simulation of Turbulence Coupling in Edge Plasma Using Message Passing Interface MPI written by Bijal Chandrakant Modi and published by . This book was released on 1995 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Developments in the Gyrofluid Approach to Tokamak Turbulence Simulations written by and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: A status report is given on recent developments in the gyrofluid approach to simulating tokamak turbulence. G̀̀yrofluid ̀̀(or g̀̀yro-Landau fluid)̀̀ equations attempt to extend the range of validity of fluid equations to a more collisionless regime typical of tokamaks, by developing fluid models of important kinetic effects such as Landau-damping and gyro-orbit averaging. The fluid moments approach should converge if enough moments are kept, though this may require a large number of moments for some processes. Toroidal gyrofluid equations have been extended from 4 to 6 moments, and to include the ? ∇B magnetic mirroring force. An efficient field-line coordinate system for toroidal turbulence simulations (useful for both particle and fluid simulations) is presented. Nonlinear 3-D simulations of toroidal ITG-driven turbulence indicate that turbulence-generated sheared flows play. an important role in the development and saturation of the turbulence. There is a strong enhancement of the flows when the electrons are assumed adiabatic on each flux surface, which is partially offset by toroidal drift effects which reduce the flows.
Download or read book Theory of Fusion Plasmas written by Olivier Sauter and published by American Institute of Physics. This book was released on 2008-12-02 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Joint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas takes place every other year in a place particularly favorable for informal and in depth discussions. Invited and contributed papers present state-of-the art researches in theoretical plasma physics, covering all domains relevant to fusion plasmas. This workshop always allows a fruitful mix of experienced researchers and students, to allow for a better understanding of the key theoretical physics models and applications, such as: Theoretical issues related to burning plasmas; Anomalous Transport (Turbulence, Coherent Structures, Microinstabilities) RF Heating and Current Drive; Macroinstabilities; Plasma-Edge Physics and Divertors; Fast particles instabilities.
