Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Numerical studies of the resistive stability of tokamak plasmas in cylindrical geometry have been performed using: (1) the full set of resistive Magnetohydrodynamic (MHD) equations and (2) an extended version of the reduced set of resistive MHD equations including diamagnetic and electron temperature effects. In particular, the nonlinear interaction of tearing modes of many helicities has been investigated. The numerical results confirm many of the features uncovered previously using the simple reduced equations.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
CPU times for nonlinear resistive MHD calculations are very strongly dependent on the input variables. Although some regions of parameter space can be studied very cheaply, the conditions that correspond to Tokamak plasmas are extremely time consuming to study. Unfortunately, it is not possible to extrapolate reliably from the easy cases to the interesting regime. In recent years we have improved the efficiency of our codes by two orders of magnitude. As a result it is now feasible for us to run some realistic Tokamak cases on a CDC 7600. An additional factor of four reduction in run time is obtained by going to the CRAY-1 where the most time consuming routines are vectorized. This last factor makes a program of systematic studies feasible.
Author: Hartmut Zohm Publisher: 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.
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Author: Hartmut Zohm
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