Abstract: This article focuses on the difficulty of plasma breakdown during the development of a micro RF ion thruster. Experimental research is conducted on the breakdown characteristics of a low pressure narrow tube inductively coupled plasma source(ICP) using simple present and simple past tenses. The plasma breakdown area in the discharge chamber was studied, and it is found that the breakdown location of the low pressure narrow tube ICPs is not in the antenna area where the electric field is strongest. That is, the breakdown area of the antenna is not in the same area as the plasma maintenance area where the RF ion thruster operates stably, making it difficult to ignite the breakdown using the traditional RF ion thruster structure. Simple present and simple past tenses are used to discuss the results of changes made to the structure of the discharge chamber and the position of the antenna to study the variation of the breakdown conditions. It is found that the above phenomenon can be improved by extending the length of the discharge chamber, increasing the number of antenna turns appropriately, and adjusting the relative position between the antenna and the discharge chamber.

Key words: ICP, low pressure narrow tube, breakdown region