다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The ITER Physics Basis presents and evaluates the physics rules and methodologies for plasma performance projections, which provide the basis for the design of a tokamak burning plasma device whose goal is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes. This Chapter summarizes the physics basis for burning plasma projections, which is developed in detail by the ITER Physics Expert Groups in subsequent chapters. To set context, the design guidelines and requirements established in the report of ITER Special Working Group 1 are presented, as are the specifics of the tokamak design developed in the Final Design Report of the ITER Engineering Design Activities, which exemplifies burning tokamak plasma experiments. The behaviour of a tokamak plasma is determined by the interaction of many diverse physics processes, all of which bear on projections for both a burning plasma experiment and an eventual tokamak reactor. Key processes summarized here are energy and particle confinement and the H-mode power threshold; MHD stability, including pressure and density limits, neoclassical islands, error fields, disruptions, sawteeth, and ELMs; power and particle exhaust, involving divertor power dispersal, helium exhaust, fuelling and density control, H-mode edge transition region, erosion of plasma facing components, tritium retention; energetic particle physics; auxiliary power physics; and the physics of plasma diagnostics. Summaries of projection methodologies, together with estimates of their attendant uncertainties, are presented in each of these areas. Since each physics element has its own scaling properties, an integrated experimental demonstration of the balance between the combined processes which obtains in a reactor plasma is inaccessible to contemporary experimental facilities: it requires a reactor scale device. It is argued, moreover, that a burning plasma experiment can be sufficiently flexible to permit operation in a steady state mode, with non-inductive plasma current drive, as well as in a pulsed mode where current is inductively driven. Overall, the ITER Physics Basis can support a range of candidate designs for a tokamak burning plasma facility. For each design, there will remain a significant uncertainty in the projected performance, but the projection methodologies outlined here do suffice to specify the major parameters of such a facility and form the basis for assuring that its phased operation will return sufficient information to design a prototype commercial fusion power reactor, thus fulfilling the goal of the ITER project.

https://iopscience.iop.org/article/10.1088/0029-5515/39/12/301/pdf

Chapter 1: Overview and summary

Nonlinear gyrokinetic equations play a fundamental role in our understanding of the long-time behavior of strongly magnetized plasmas. The foundations of modern nonlinear gyrokinetic the- ory are based on three important pillars: (1) a gyrokinetic Vlasov equation written in terms of a gyrocenter Hamiltonian with quadratic low-frequency ponderomotive-like terms; (2) a set of gyrokinetic Maxwell (Poisson-Ampere) equations written in terms of the gyrocenter Vlasov dis- tribution that contain low-frequency polarization (Poisson) and magnetization (Ampere) terms derived from the quadratic nonlinearities in the gyrocenter Hamiltonian; and (3) an exact energy conservationlaw for the gyrokineticVlasov-Maxwell equations that includes all the relevant linear and nonlinear coupling terms. The foundations of nonlinear gyrokinetic theory are reviewed with an emphasis on the rigorous applications of Lagrangian and Hamiltonian Lie-transform perturba- tion methods used in the variationalderivationof nonlineargyrokineticVlasov-Maxwell equations. The physical motivations and applications of the nonlinear gyrokinetic equations, which describe the turbulent evolution of low-frequency electromagnetic fluctuations in a nonuniform magnetized plasmas with arbitrary magnetic geometry, are also discussed.

/pdf/foundations-of-nonlinear-gyrokinetic-theory-3l78lnlpai.pdf

Foundations of nonlinear gyrokinetic theory

http://www.xsciforge.com/about/articles/nubeam.pdf

The tokamak Monte Carlo fast ion module NUBEAM in the National Transport Code Collaboration library

Low-temperature plasma physics and technology are diverse and interdisciplinary fields. The plasma parameters can span many orders of magnitude and applications are found in quite different areas of daily life and industrial production. As a consequence, the trends in research, science and technology are difficult to follow and it is not easy to identify the major challenges of the field and their many sub-fields. Even for experts the road to the future is sometimes lost in the mist. Journal of Physics D: Applied Physics is addressing this need for clarity and thus providing guidance to the field by this special Review article, The 2012 Plasma Roadmap.

/pdf/the-2012-plasma-roadmap-3pk2a2bghd.pdf

The 2012 Plasma Roadmap

The formalism to describe the saturation of a discrete mode that is destabilized by hot particles fed by neutral beam injection is extended. The destabilization mechanism described in this work arises from the density gradient in the distribution function formed from a spatially inhomogeneous source. Energetic particles are injected at a fixed speed and collisionally relax through drag and pitch‐angle scattering with the background plasma. The distribution formed is solved self‐consistently in the presence of a finite amplitude wave in a sheared magnetic field. Three regimes of collisionality are found and the expressions for the nonlinear wave–particle power transfer is determined in each regime. With the dissipation processes of the background plasma given, the wave saturation level is then determined. When pitch‐angle scattering is sufficiently weak, particles trapped in a wave convect across the magnetic field as they slow down, a phenomenon similar to the Ware pinch.

Saturation of a single mode driven by an energetic injected beam. II. Electrostatic ``universal'' destabilization mechanism

Finite orbit energetic particle linear response to toroidal Alfven eigenmodes

A numerical procedure has been developed for the self‐consistent simulation of the nonlinear interaction of energetic particles with discrete collective modes in the presence of a particle source and dissipation. A bump‐on‐tail instability model is chosen for these simulations. The model presents a kinetic nonlinear treatment of the wave–particle interaction within a Hamiltonian formalism. A mapping technique has been used in this model in order to assess the long time behavior of the system. Depending on the parameter range, the model shows either a steady‐state mode saturation or quasiperiodic nonlinear bursts of the wave energy. It is demonstrated that the mode saturation level as well as the burst parameters scale with the drive in accordance with the analytical predictions. The threshold for the resonance overlap condition and particle global diffusion in the phase space are quantified. For the pulsating regime, it is shown that when γL≳0.16 ΔΩ, where γL is the linear growth rate for the unperturbed ...

/pdf/numerical-simulation-of-bump-on-tail-instability-with-source-3kenkpdddp.pdf

Numerical simulation of bump‐on‐tail instability with source and sink

A nonlinear theory has been developed to describe electron response and ion acceleration in dense clusters that are smaller in size than the laser wavelength. This work is motivated by high-intensity laser-cluster interaction experiments. The theory reveals that the breakdown of quasineutrality affects the cluster dynamics in a dramatic way: the laser can create a positively charged ion shell that expands due to its own space charge much faster than the central part of the cluster. The developed theory also shows a trend for the electron population to have a two-component distribution function: a cold core that responds to the laser field coherently and a hot halo that undergoes stochastic heating. The hot electrons expand together with the equal number of ions that are accelerated to supersonic velocities in a double layer at the cluster edge. This mechanism produces fast ions with energies much greater than the ponderomotive potential and it suggests that larger deuterium clusters can significantly enhance the neutron yield in future experiments.

/pdf/nonlinear-physics-of-laser-irradiated-microclustersa-31aqr0onsg.pdf

Nonlinear physics of laser-irradiated microclustersa)

A new nonlinear equation has been derived and solved for the evolution of an unstable collective mode in a kinetic system close to the threshold of linear instability The resonant particle response produces the dominant nonlinearity, which can be calculated iteratively in the near-threshold regime as long as the mode doe snot trap resonant particles With sources and classical relaxation processes included, the theory describes both soft nonlinear regimes, where the mode saturation level is proportional to an increment above threshold, and explosive nonlinear regimes, where the mode grows to a level that is independent of the closeness to threshold The explosive solutions exhibit mode frequency shifting For modes that exist in the absence of energetic particles, the frequency shift is both upward and downward For modes that require energetic particles for their existence, there is a preferred direction of the frequency shift The frequency shift continues even after the mode traps resonant particles

/pdf/nonlinear-theory-of-kinetic-instabilities-near-threshold-503mbwn1zl.pdf

Boris Breizman

Papers

Saturation of a single mode driven by an energetic injected beam. II. Electrostatic ``universal'' destabilization mechanism

Finite orbit energetic particle linear response to toroidal Alfven eigenmodes

Numerical simulation of bump‐on‐tail instability with source and sink

Nonlinear physics of laser-irradiated microclustersa)

Nonlinear theory of kinetic instabilities near threshold