Spatiotemporal study of gas heating mechanisms in a radio-frequency electrothermal plasma micro-thruster

Frontiers in Physics

Boswell, Roderick W.¹  Charles, Christine¹  Greig, Amelia¹ 

[1] Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT, Australia

关键词: Plasma heating;    rovibrational spectroscopy;    electric propulsion;    Thermal Conductivity;    Charge exchange collisions;    Ion bombardment;   

DOI  :  10.3389/fphy.2015.00084

学科分类：物理（综合）

来源: Frontiers

【 摘 要 】

A spatiotemporal study of neutral gas temperature during the first 100 s of operation for a radio-frequency electrothermal plasma micro-thruster operating on nitrogen at 60 W and 1.5 Torr is performed to identify the heating mechanisms involved. Neutral gas temperature is estimated from rovibrational band fitting of the nitrogen second positive system. A set of baffles are used to restrict the optical image and separate the heating mechanisms occurring in the central bulk discharge region and near the thruster walls. For each spatial region there are three distinct gas heating mechanisms being fast heating from ion-neutral collisions with timescales of tens of milliseconds, intermediate heating with timescales of 10 s from ion bombardment on the inner thruster tube surface creating wall heating, and slow heating with timescales of 100 s from gradual warming of the entire thruster housing. The results are discussed in relation to optimising the thermal properties of future thruster designs.

【 授权许可】

CC BY