Kai Aoyama1,Shinichiro Shobako1,Tomohiko Yamashita1,Noboru Terajima1,Manabu Tanaka2,Hisaya Komen2
National Institute of Technology Kagawa Collge1,Joining and Welding Research Institute, Osaka University2
Kai Aoyama1,Shinichiro Shobako1,Tomohiko Yamashita1,Noboru Terajima1,Manabu Tanaka2,Hisaya Komen2
National Institute of Technology Kagawa Collge1,Joining and Welding Research Institute, Osaka University2
NASA announced the Mars manned exploration plan in the 2030s. And Elon Musk, SpaceX’s CEO insisted that human must consider moving to the Mars to avoid possibility of human extinction by global warming and recent changes in our climate. That’s why basic research and technological development for Mars exploration are actively carried out around the world. If human would emigrate to the mars, it’s necessary that constructions are built in there. In that case Welding techniques are necessary for keeping airtight of constructions in low Martian atmospheric pressure. And materials of constructions in Mars are predicted aluminum alloys which lightweight and transportable. Thus AC-GTA (Alternative Current-Gas Tungsten Arc) welding which is aluminum alloy’s welding method is expected as a technique for constructing in Mars. On the other hands, Mars is about one hundredth of the atmospheric pressure of the earth (about 750 Pa) and is a carbon dioxide atmosphere. Therefore, the plasma characteristics of AC-GTA in the atmosphere of Mars must be investigated. In this report, in order to investigate the characteristics of AC-GTA in the Martian atmosphere, like Mars atmosphere was made in vacuum chamber and AC-GTA was generated in there. The Martian atmosphere was simulated by introducing CO<sub>2</sub> gas to decompressed vacuum chamber and regulating the pressure. As examination of the plasma characteristics of AC-GTA in the like Martian atmosphere, electron density distribution of AC-GTA was measured. To measure the electron density distribution, the infrared plasma diagnostic method (IR method) was used. IR method is analytical method that estimate electron density from infrared images of arc plasma. For taking AC-GTA infrared images at 200 Hz, high speed camera equipped with bandpass filter of 960 nm was used. The electron density distribution of AC-GTA in the like Mars / Earth atmosphere were calculated by IR method, and these results were compared. It was shown plasma characters of AC-GTA in like Mars atmosphere.