Developments of Mutiple Pellet Injectors

建立了两种多弹丸喷射器并进行了试验：(1)采用外置式，一次射出5颗弹丸。但是，时间间隔被限制在大约150毫秒。其原因可能与外点附近残留的推进剂气体有关。(2)采用转盘式，可同时射出6颗弹丸，且发射时间延迟(30-50ms)。该装置的弹丸速度为1.1公里/S，适用于氦加速器E的弹丸注入实验。设计了(3)管枪式和(4)离心式两种类型。这些似乎也很有希望。为提高密度剖面控制的灵活性，研制了改变颗粒飞行方向的驱动机构。还利用快速相机(曝光时间为20us)对弹丸烧蚀进行了实验研究。

Two types of multiple pellet injectors are constructed and tested;(1) By an extrunder type, 5 pellets are shot out in one sequence. But, the time interval is limited at about 150 ms. The reason may be due to the residual propellant gas near the exterunding point.(2) By a rotating disk type, 6 pellets are shot out in the same time, and also delayed (30-50 ms). The pellet valocity is 1.1 Km/s. This type is very useful for pellet injection experiments in Heliotron E. the other two types, that is, (3) pipe gun type, and (4) centrifugal type, are designed. These seem to be also promising. The driving mechanism for changing pellet flight direction is developed for increasing flexibility of density profile control. The pellet ablation is also expermentally studied by using a fast camera (20 us exposure time).