Abstract: The heat-resistant materials on the surface of high-speed aircraft may be decomposed and ablated under the high temperature generated by aerodynamic heating. After the ablated products enter the flow field, they react with the high-temperature air in the flow field, thus affecting the component concentration and plasma distribution in the air flow field around the aircraft. A high-temperature supersonic air flow is generated by high-frequency induction heating in a high-frequency plasma wind tunnel. A high-temperature flow field is formed around a pure carbon-carbon material model and a water-cooled copper model with the same shape. The electron number density at the different heights of distance model was measured by using Langmuir probe. The experimental results show that, when the pure carbon-carbon material model is in an obvious ablation state, the ablated products affect the electronic number density in the flow field, which is less than that in the pure air flow field of the water-cooled copper model; and the electronic number density in the flow field of multiple samples of the pure carbon-carbon material model after ablation decreases with the increase in the mass ablation rate. The ablated products only affect the electron number density in the flow field at a certain distance from the wall, and the electron number density in the flow field far away from the wall is close to that in the pure air flow field.

Key words: aircraftpurecarbon-carbonmaterial, ablation, plasmaflowfield, electronnumberdensity