. One important method for fusion plasma heating is the using of radio waves. In recent years there has been considerable interest in generating steady-state currents in plasma with RF waves. In particular, it was predicted that these currents could be efficiently generated by waves having phase velocities several times the electron thermal speed. This prediction has been confirmed by numerous experiments in which the current was driven by lower-hybrid waves. These results allow us to contemplate a steady-state tokamak reactor in which the toroidal current is driven by lower-hybrid waves. From a theoretical point of view, the main component in these experiments is the dc electric field, which opposes the increase of the plasma current. The electric field is also present in schemes where the RF is used to recharge the transform at constant current. This theory was also predicted that RF energy could be efficiently converted to poloidal field energy, if the wave phase velocity were approximately equal to the electron runaway velocity. Poloidal field compresses the plasma and the plasma edge heats dissipation and it will prevent possible further treatment that leads to fusion for us. The interaction of radio-frequency waves with plasma is described by a Fokker-Planck equation with an added quasi-linear term that presence of such sentence can be searched in particle collisions.To solve this equation, take the plasma then to be azimuthally symmetric about the magnetic field and homogeneous, the Fokker-Planck equation then reduces to an equation in time and two velocity dimensions.This simplified model yields a wealth of interesting physics and furthermore illustrates the main numerical problems encountered in more complicated situations. In addition to the collision term, the equation will include the effects of externally injected RF power via a quasi-linear diffusion term, and a dc electric field. We have used LSC code for computation of the Fokker-Planck equation and simulation of lower hybrid waves injected. The Lower hybrid Simulation Code (LSC) is a computational model of lower hybrid current drive in the presence of an electric field. Details of geometry, plasma profiles and circuit equations are treated. Two-dimensional velocity space effects are approximated in a one-dimensional Fokker-Planck treatment. In this project, simulation of injected lower hybrid waves for NSTX,MAST,JET andDIII–D tokamaks have been performed. The results of this project show that spherical torus have better performance than torque tokamaks. This condition causes the fusion reaction self-sustaining realized, should be better and the possibility of nuclear fusion power and performance is provided. Key Words Lower hybrid waves (LH), Fokker-Planck equation, diffusion quasi-linear, LSC code, NSTX, MAST, JET andDIII–D tokamaks.
