Experimental research of wake electron density of hypersonic sphere models

In this paper, wake electron density of hypersonic sphere models has been measured in ballistic range, CARDC.The electron density measurement system is made up of 8mm micro-wave interferometer, open microwave cavity measurement system and closed microwave cavity measurement system.The diameter of the steel sphere models is 10mm.The model velocities are 5.8, 5.5, 5.6 and 5.5km/s. The corresponding flight environmental pressures are 2.79、5 32、 5.85 and10.91kPa.The diameter of copper sphere models is 10mm.The results present the wake electron density of steel sphere models is larger as a result of high environment pressure under the test conditions of the pressure ranged from 5.3kPa to 11kPa, speed 5.5km/s.The composite speed is quick under the conditions.The wake electron density of copper sphere models is larger as a result of high environment pressure under the test conditions of the pressure ranged from 1.3kPa to 6kPa, speed 5.6km/s test conditions. The composite speed is slow under the condi-tions.The composite speed of copper sphere models is slower than that of the steel sphere models under the conditions of the pressure 10.7kPa and speed 5.5km/s.