Author: Publisher:
ISBN:
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Languages : en
Pages : 44
Book Description
Kinetic Analysis of MHD Ballooning Modes in Tokamaks
Author: Theory of Tokamak Plasmas
Author: R.B. WhitePublisher: Elsevier
ISBN: 1483293262
Category : Science
Languages : en
Pages : 374
Book Description
This is a graduate textbook on tokamak physics, designed to provide a basic introduction to plasma equilibrium, particle orbits, transport, and those ideal and resistive magnetohydrodynamic instabilities which dominate the behavior of a tokamak discharge, and to develop the mathematical methods necessary for their theoretical analysis.
Local Kinetic Analysis of the Ballooning Mode in Tokamaks
Author: Akira HiroseInfluence of Hot Beam Ions on MHD Ballooning Modes in Tokamaks
Author: Publisher:
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Languages : en
Pages :
Book Description
It has recently been proposed that the presence of high energy ions from neutral beam injection can have a strong stabilizing effect on kinetically-modified ideal MHD ballooning modes in tokamaks. In order to assess realistically the importance of such effects, a comprehensive kinetic stability analysis, which takes into account the integral equation nature of the basic problem, has been applied to this investigation. In the collisionless limit, the effect of adding small fractions of hot beam ions is indeed found to be strongly stabilizing. On the other hand, for somewhat larger fractions of hot ions, a new beam-driven mode is found to occur with a growth rate comparable in magnitude to the growth rate of the MHD ballooning mode in the absence of hot ions. This implies that there should be an optimal density of hot particles which minimizes the strength of the relevant instabilities. Employing non-Maxwellian equilibrium distribution functions to model the beam species makes a quantitative, but not qualitative, difference in the results. Adding collisions to the calculation tends to reduce considerably the stabilizing effect of the hot ions.
Theory of Kinetic Ballooning Modes Excited by Energetic Particles in Tokamaks
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 19
Book Description
We have analyzed theoretically the resonant excitations of kinetic ballooning modes (KBM) by the energetic ions/alpha particles in tokamaks. Our theory includes finite-size orbit effects of both circulating and trapped particles. With energetic-particle contributions suppressed in the singular inertial layer, an analytic.dispersion relation can then be derived via an asymptotic matching analysis. The dispersion relation, in particular, demonstrates the existence of two types of modes; that is, the magnetohydrodynamic (MHD) gap mode and the energetic-particle continuum mode. Specific expressions for real frequencies, growth rates and threshold conditions are also derived for a model slowing-down beam ion distribution function.
Magnetohydrodynamic Stability of Tokamaks
Author: Hartmut ZohmPublisher: John Wiley & Sons
ISBN: 3527412328
Category : Science
Languages : en
Pages : 254
Book Description
This book bridges the gap between general plasma physics lectures and the real world problems in MHD stability. In order to support the understanding of concepts and their implication, it refers to real world problems such as toroidal mode coupling or nonlinear evolution in a conceptual and phenomenological approach. Detailed mathematical treatment will involve classical linear stability analysis and an outline of more recent concepts such as the ballooning formalism. The book is based on lectures that the author has given to Master and PhD students in Fusion Plasma Physics. Due its strong link to experimental results in MHD instabilities, the book is also of use to senior researchers in the field, i.e. experimental physicists and engineers in fusion reactor science. The volume is organized in three parts. It starts with an introduction to the MHD equations, a section on toroidal equilibrium (tokamak and stellarator), and on linear stability analysis. Starting from there, the ideal MHD stability of the tokamak configuration will be treated in the second part which is subdivided into current driven and pressure driven MHD. This includes many examples with reference to experimental results for important MHD instabilities such as kinks and their transformation to RWMs, infernal modes, peeling modes, ballooning modes and their relation to ELMs. Finally the coverage is completed by a chapter on resistive stability explaining reconnection and island formation. Again, examples from recent tokamak MHD such as sawteeth, CTMs, NTMs and their relation to disruptions are extensively discussed.
Fusion Energy Update
Author: Fluid Analysis of the Collisionless MHD Ballooning Mode Branch in Tokamaks
Author: Hans NordmanInfluence of Diamagnetic Drifts on Critical Beta in Tokamaks
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In specific cases the critical beta (.beta./sub c/) for stability against internal magnetohydrodynamic (MHD) ballooning modes can be improved significantly by taking into account the stabilizing influence of the ion diamagnetic drifts. This kinetic modification to the ideal MHD analysis together with radial corrections to the local theory are included in a calculation of .beta./sub c/ as a function of toroidal mode number (n) for a particular tokamak equilibrium sequence of interest.
Author: M. Elia