The Preparation And Study On D2 Cluster For Laser-cluster Fusion

More recently, accompanied by progresses on the technique of chirped pulse amplification, the interaction of clusters with picoseconds and femtosecond lasers has attracted considerable interest. Cluster interaction with ultra-short pulse ultra-high intense laser leads to column exploding, and it can produce deuterium ion with energy about MeV. Thus it provides people with a brand new idea to achieve fusion in reaction in lab. Due to the significant impact of characteristic of cluster on the cluster-laser interaction experiment, the thesis just points to characterization of cluster used in the interaction experiment.Some basic knowledge related to cluster is introduced from scratch, and then it's outlined that progresses and application prospect of research on the cluster interaction with ultra-short pulse ultra-high intense laser. Great effects on characterization of clusters have been made by groups over the world. The thesis elucidates and makes preparatory comparison about these methods, also relevant conclusions.The thesis encloses studies on mechanism of cluster formation by different methods. A low temperature deuterium cluster source assembly based on supersonic expansion is constructed and used to interaction, cooling installation, pulse solenoid valve, nozzle and location adjusting installation. When backing pressure is 48atm, temperature 100K, clusters produced via the cluster source assembly is measured with a size of 2360 atoms/cluster, and its density is as high as 3.5×10¹⁹ atoms/cm³. The system provides preconditions of the interaction experiment and make it possible. Some theoretical research on characteristics of cluster is made, numerical simulation is applied to calculation the density profile and rule of cluster size transition. It's set forth that principle of M-Z interferometry technique and Rayleigh scattering measurement, corresponding experimental diagnostic system is constructed. Spatial density profile of gas jet is obtained via the interferometer pattern, and Rayleigh scattering measurements show cluster size and condensation degree. The two experimental systems perform with good stability. Both of them are synchronized in space dimension and time dimension with the cluster source assembly.Processing data methods are probed, mainly about the Interferometer pattern via M-Z interferometry. And a program based on Fourier transform was performed analyze the interferometer pattern, which is of a higher precision and stability. The good nature of the program is confirmed primarily in experiments.M-Z interferometry shows jet density profile at a range of backing pressures and temperatures. (a).Analyze the density transition at orifice with backing pressure, temperature, geometrical dimension and so forth. It confirms well to simulation results. Under theory's instruction, combined with rule of density profile revealed in experiment, a semi experiment formula is obtained, which will illustrate jet density profile in axis dimension and radius. (b).Shift the time interval between gas puff into vacuum and laser firing, namely relative time-lapsed, density profile transform with time elapsed is acquired. It shows that there is a time extent in which the density maintains at a max level, correspondingly, a quite stable state of cluster source assembly exists. (c).In contrast to results of Rayleigh scattering, average density of a spot at the axis with 2mm distance from orifice is obtained at a range of backing pressure. It concludes that cluster size grows with backing pressure increasing at a given temperature, also condensation. But the number of clusters is in inverse proportion to backing pressure increasing, which reveals that clusters growth faster than its productivity.Comparing theoretical calculation and experiment results from groups abroad, an evaluation is made for performance of the cluster source assembly in cluster fusion experiments. The capability of the cluster source assembly equals to its counterpart installed by research groups overseas, and is expected to create favorable conditions for cluster fusion experiment domestic.