Developments of Mutiple Pellet Injectors

构建并测试了两种类型的多颗粒注入器；(1)采用挤出机，一次连续挤出5粒球。但是，时间间隔被限制在150毫秒左右。其原因可能是在燃点附近残留了推进剂气体。(2)采用旋转盘式，同时出丸6粒，也有延迟（30-50 ms）。颗粒速度为1.1 Km/s。这种类型对Heliotron e的颗粒注射实验非常有用，设计了另外两种类型，即(3)管枪型和(4)离心型。这些似乎也很有希望。为提高颗粒密度分布控制的灵活性，研制了改变颗粒飞行方向的驱动机构。利用快速相机（曝光时间为20 us）对微球消融进行了实验研究。

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).