The Nonlinear Diffusion in the Nonisothermical Case |
| A.J. Janavičius Šiauliai University, P. Višinskio 25, 5400 Šiauliai, Lithuania |
| Received: October 3, 1997; in final form December 2, 1997 |
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| We will discuss the properties of the nonlinear equation in the nonisothermical case. In our previous papers the diffusion coefficient directly proportional to the concentration of the impurities was proposed and it was exactly defined. Now the nonlinear diffusion equation is solved for the temperature and for the diffusion coefficient depending on time in a special way. The temperature function T(t) has the singularity at the free chosen time moment t0. The obtained analytical solutions define the diffusion profiles for increasing temperatures and in the case of excited systems when the vacancies and the impurity's atoms are not in the thermal equilibrium with lattice. Considering the connection between temperature function and the population of excited states for atoms surrounding vacancies the possibility of the superdiffusion is shown. |
| DOI: 10.12693/APhysPolA.93.505 PACS numbers: 66.30.-h |