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.

Effects of external current drive on instability of double tearing mode in Hall MHD equations are numerically investigated. It shows that double tearing mode can be suppressed by antiparallel external current drive at x-point of tearing mode magnetic islands. Periodic external current drive controls island width under a threshold and stabilizes double tearing mode. With increasing period depression effect becomes worse. If frequency, density and width of periodic external current drive are adopted suitably, depression effect becomes better.

Heating of magnetized plasmas by low-frequency Alfvén waves propagating along background magnetic field is studied with test particle simulation.It shows that ions in perpendicular and parallel directions of the background magnetic field are heated significantly.In a stage of non-resonance heating,perpendicular heating is more significant than parallel heating,and anisotropic temperature comes into being.In a stage of stochastic heating,perpendicular and parallel temperatures of ions finally reach saturation and convergence.In heating process,the maximum kinetic temperature of ions is dependent on the ratio of magnetic field energy density and plasma density,which has no relevance with Alfvön-wave frequency and amplitude.Ions are significantly accelerated in parallel direction.and attained a bulk speed that is roughly equal to phase velocity of Alfvén waves.

Shear flows in resonant surfaces of Tokamka devices induced by nonhnear evolution of double tearing modes(DTM) are studied numerically in the framework of resistive magnetohydronamic model with slab geometry.It is found that in early phases of nonlinear evolution of DTM,no remarkable shear flows is generated in resonant surfaces.Effective shear flows emerge during the phase of fast magnetic reconnection and disappear finally.Both amplitude and distribution of shear flows are found vary with nonlinear evolution of magnetic islands.Moreover,by taking into account plasma resistivity,it is shown that greater plasmas resistivity results in faster magnetic reeonection, but it hardly affects shear flows of resonant surfaces in Tokamka devices.