Heating of magnetized plasma through one towards mutiple shear Alfvén waves with low frequency propagating along background magnetic field is studied with test particle simulation.It shows that mutiple waves whose frequencies match resonance condition lead to significantly efficiency heating by strengthen non-resononce process. With evolution of heating, mutiple waves turn to modulation wave. As frequencis of mutiple waves are close wave packets are created in transverse direction. A great ion temperature anisotrophy is produced and after that randomization process is stengthened either. Efficiency of stochastic heating process is also enhanced.It can be used in controling non-resonance and stochastic heating process by changing frequencise of mutiple low frequency waves.

We deal with one-dimensional source inverse heat conduction equation. An approach based on least squares support vector machines (LS-SVM) is proposed for semi-analytic approximate solutions. Furthermore, a parameters tuning formulism is shown and stability of the method is presented. The method yields high accuracy and stability solutions in practical examples.

A post processing method for smoothed particle hydrodynamics data is presented on basis of Delaunay triangulation.Pairing particle set in scope of each particle in flow field is confirmed,and then discretized by Delaunay triangulation on condition of present pairing particle set,which leads to a set of triangle elements with particles as nodes.At last non material units are filtered.Examples indicate that SPH result with complex boundary conditions and severe deformation of fluid region can be treated.

For efficient calculation of neutronic-thermal hydraulic coupling in pebble bed high temperature gas cooled reactor,a modified nodal expansion method (MNEM) was developed to solve convection-diffusion equation in cylindrical geometry.Within the framework of nodal expansion method,up to third-order polynomials combined with an orthogonalizd exponential function were adopted as basis functions for r-directed transverse integrated equation.Numerical tests reveal that the MNEM posses inherent upwind characteristic,and has good accuracy and stability for coarse meshes.