The solution of nonlinear parabolic equation using variational iteration method

Variational iteration method is a semi analytic solution used to solve the parabolic differential equation both of homogen or nonhomogen. In the process of determining an approximation solution, this method did not use a linearization and a small pertubation. In this paper, the variational iteration method is implemented in the parabolic differential equation in the form of ut = uxx + f(u) + g(x, t) with appropriate intial condition. Furthermore, some examples of special parabolic differential equations are given to test the reliability and convergence of the method. Based on the result of study shows that the variational iteration method is able to solve the parabolic differential equation with a good accuration.

Non-equilibrium Ionisation in Tycho’s Supemova Remnant

We present a detailed numerical study of the X-ray emission of Tycho’s supernova remnant. Using Nomoto’s W7 model of an exploding white dwarf as intial condition we follow the hydrodynamical and ionisation evolution for different densities of the interstellar medium and compare the emitted spectra with EXOSAT GSPC observations. The results indicate that the density of the ambient medium is 0.5 ≤ no ≤ 1.0 cm-3, the distance to Tycho is about 3 kpc.