Development of Pellet Injecitn Method with the Continuous-Controllability of Pellet Size and Studies on the Injection into Plasmas

为了研究弹丸注入环形等离子体的基本性质，要求弹丸注入器具有可重复性和可控性。到目前为止，在一些地方已经开发了几个注射器，其中一个可以在一定程度上改变颗粒大小。然而，他们只能以离散的方式改变它。在我们的研究中，为了开发一种连续的尺寸可控技术，设计和建造了一种新的喷射器，它是通过使用一种特殊的颗粒长度限制杆来改变颗粒尺寸的。第一个结果并不令人满意，即所获得的颗粒尺寸与预设值不一致。部分原因被认为是因为固体氢与限长棒金属表面的附着力可能扰乱了预期的操作，部分原因是用于生产冰球的氢气压力也可能…更多的材料扰乱了预期的操作。各种材料已经作为限长杆头和其上的涂层材料进行了测试。并对冰球生产部分有无氢气时的结果进行了对比实验。此外，还考察了不同形状的球团生产腔对球团与杆件附着力的影响。这些结果都显示了不同程度的效果，但都不是十全十美的。最后，对操作程序在控制球团粒度方面的改进进行了考虑和试验。其想法是改变球团的生产位置，以消除固体氢和限长棒表面附着的可能性。最终结果表明，观测值与预设值之间有很好的一致性。弹丸的大小是在弹丸从枪口弹出后立即用高速取景照片测量的。利用这一新开发的注射器，进行了各种喷射实验，观察到了一些有趣的现象。较少

In order to study basic properties of toroidal plasmas by pellet injection, it is extremely desirable for the pellet injector to be reproducible and to be controllable. Until now, several injectors were developed in some places, where one could vary pellet size to a certain extent. However, they could vary it only in a discrete manner. In our present study, a new injector has been designed and constructed in order to develop a technique with continuous size-controllability.The injector has been developed so as to vary a pellet size by using a special technique of a pellet-length limiting rod. The first results were not satisfactory ; that is, the obtained pellet sizes were not consistent with the presetting values. The reason was ocnsidered to be partially because that an attachment force of solid hydrogen and metal surface of the length-limiting rod might have disturbed the expected operation, and partially because that the pressure of hydrogen gas for producing ice pellet might also … More have disturbed the expected operation.Various materials has been tested as a head of length-limiting rod and as a coating stuff on it. Experiments for comparison ofthe results with and without the hydrogen gas in the ice pellet production part have also been carried out. In addition to these studies, the effect of various shape of the pellet production cavity has been examined, which might have some influence in rsisting the attachment force of a pellet and the rod. Those results showed each effect to some extent, but each of it was not a perfect one.Finally the improvement of the operaiton procedure in controlling a pellet size has been considered and tested. The idea is to change the pellet production position in order to eliminate the possibility of attachment of solid hydrogen and the surface of the length-limiting rod. The final results show very good agreemtne between the observed size and the presetting value. The pellet size has been measured by using a high-speed framing photograph just after the ejection from the muzzle. Thus, the technique will become a useful method for this field.By using this newly developed injector, various injection experiments have been carried out, and several interesting phenomena have been observed. Less