The Research For The Formation Of Binary H-D Mixture ICF Target By Thermal Gradient Method

Since the 20th century, the mankind was facing the more and more serious energy crisis and environmental crisis. Inertia confinement fusion is the most effective method to solve human energy problems for a long time. The non-contact thermal gradient method for fabrication of uniform cryogenic inertial fusion target is investigated in this Thesis. A model was to be developed to describe the thermally induced behavior of liquid layer of hydrogen isotopes inside a spherical ICF target and to calculate the far-field temperature gradient which will sustain a uniform liquid layer and the relevant near-field temperature gradient. The governing equations used to develop the model are the equations of continuity, momentum, energy, and mass diffusion-convection. The significance of the surface tension gradient induced by the component separation at the liquid-vapor interface driven flows(also called Marangoni flows)in forming uniform liquid layers inside ICF target is demonstrated. By using the boundary conditions such as the balance of the shear stress condition, the non-slip condition at the liquid-SGS interface and the continuity of the velocity on boundary, a self-consistent numerical model has been developed by using the method of vorticity and stream function. Using the theoretical model ,the value of the thermal gradient that give rise to the uniform liquid layers of hydrogen inside a cryogenic spherical-shell ICF target are calculated, and the result compared with the existing experimental data.A cryostat used to fabricate cryogenics target by the thermal gradient method is designed. Upper and nether thermal pole are used to make the sample box cooling down. With the use of electric heater and temperature controller, the average temperature of the sample box can be controlled to rang between 10 and 40 K, and uniform thermal gradient can be achieved.The result shows: The results of calculation model accord with the existing experimental data very well, which identify that the model can disclose the qualitative relationship among the parameter of the ICF target in despite of the simplification in the process of model establishment; A uniform liquid layer inside the cryogenic multicomponent target is obtained when the top of the target is kept warmer than its bottom, i.e.,the external linear thermal gradient is required to be positive; With the increase of the target average temperature, the external linear thermal gradient imposed on the target is also be increased; In addition, by analyzing the result of model ,it can be shown that when the other parameters is unaltered, with the increase of the target diameter the thermal gradients that give rise to uniform liquid layers are also increased accordingly.