Screening of Meteoroids by Ablation Vapor in High-Velocity Meteors

The ablation is calculated of non-fragmenting 10−2 to 10 cm sized meteoroids for typical Leonids with a velocity of 72 km/s at altitudes of about 90–110 km. At altitudes below the onset of intensive evaporation, a dense vapor cloud is formed around the body. This vapor cloud screens the meteoroid surface from direct impacts of air molecules. A particle beam model is developed that describes the air meteoroid interaction. Based on this model, the physical parameters of the vapor cloud are calculated and compared with observations collected during the Leonid Multi-Instrument Aircraft Campaign. General agreement with measured temperatures is found. In addition, boundaries of the model's applicability to specific encounter conditions are given.