No abstract available

No abstract available

No abstract available

[en] The evolution of a tokamak plasma on the diffusion-time scale is described by a two-dimensional magnetic configuration equation and a set of one-dimensional transport equations averaged over magnetic surfaces. A numerical code has been developed for the simplified version which calculates only the magnetic configuration and the electron energy and magnetic flux diffusion. Preliminary computational results are presented

[en] The strong dependence of fusion reaction rate on ion temperature leads to a thermal instability of D T burning plasma. Mathematical qualities are discussed for the non-linear differential equations describing the steady state power balance of a D T burning plasma. Shooting method is used to obtain equilibrium solution and eigenvalue of the linearized equation about temperature perturbation around equilibrium. However, the solution obtained by the above method can be different from the time-dependent one for t→∞. This provides a typical example of a kind of unsolved non-linear mathematical problem

[en] Advanced tokamak configurations are very important for achieving magnetic confinement control of nuclear fusion. However, in some case accurate computation of the configuration poses a formidable challenge. Such as there is a change of physical variable with gradient in local domain or with great difference of the order of its magnitude in the domain, in order to guarantee numerical convergence for solving plasma equilibrium equation, two trouble issues arise as the following: (1) Required computer memories increase so rapid as to restrict computation to some physical mode. (2) The order of matrix for solving algebraic equations increases so greatly that the accumulated round off errors can swamp the true solutions. The authors adopt two kinds of different mesh refinement process combining extrapolation of difference solution for more accurately solving tokamak plasma equilibrium equation. The numerical test and theoretical analysis show that the methods are robust. (10 refs., 3 tabs., 2 figs.)

[en] The linear behavior of the double tearing mode (DTM) mediated by parallel electron viscosity in cylindrical plasmas with reversed magnetic shear is numerically investigated. The mode structures and dispersion relations for linearly unstable modes are calculated. A detailed analysis of linear instability characteristics of DTMs with various roles,including the inter-resonance distance, the electron viscosity Reynolds number and poloidal mode number, is performed. (authors)