In this paper we study the laser plasma turbulent heating due to parametric instabilities by the numerical simulation method based on one and a half-dimensional cloud-in-cell scheme.The computer simulation results show that linear growth rate of the parametric instabilities is in reasonable agreement withthe theoretical predic tion. We also give the computer simulation results on no-nlinear heating rate,the heated electron distribution function,the ripple surfaceof the critical density and the caviton, These results are discussed.

We have studied parametric heating caused by electric field of strong laser with frequence which is a little higher than plasma frequence(w₀=1.1W_p)by use one and half dimensional CIC scheme. Results shown that both the ion-acoustic instabilities and the oscillation two-stream instabilities are stimulated together, nonlinear saturation show some fine structures, plasma is heated strongly and tur-blent spectra after saturetion fllows a typical power law.

We have developed a method to solve X-ray spectra. The method includes a iterative with range limit and a periodic smoothing. Better resuts had been obtained by use the method to solve X-ray spectra in laser nuclear fusion. This paper places stress on introduction the smoothing technique in the method. A smoothing weigh fuction was formed and iterative spectra was treated periodically by the weigh fuction in iterative Course. Computational results show, Numerical structure producted in iterative course of X-ray spectra was eliminated and convergence of iterative was improved and level of solving spectra was raised by using the techn-ique. physics bases of smoothing are discussed, a theoretical analyses about smoothing and experiemental results on number of smoothing and weigh fuction are given in this Paper.

Plasma particle simulation wave spectral response to electrostatic wave is systematically analyzed. We introduce the wave spectral-response function of plasma particle simulation.The response expre-sion in following case is derived respectively, Finite-Size-Particle with Gauss, triangle and square shape, its dipole expansion near grid point, finite difference and FFT solving process of Poisson equation. The influence of shape, size and treatment of Finite-Size-Particle, space discreteness and solving process of Poisson equation on particle simulation spectral response and the depression of short wave noise are discussed.

The noise-restraining mechanism due to introducing periodical smoothing in phase space in the particle simulation is analyzed. We introduce a concept of filtrate effect of the smoothing and give a analytical expression for filtrate wave coefficent that is dependent on wavelength.The results obtained show that the smoothing restrain is mainly for short wave noises and no energy transfer happens in wavenumber space.