IS THERE ANY MECHANISM CAPABLE OF PRODUCING THE SAME FRESNEL CHARACTERISTICS AS FRAGMENTATION OF METEOROIDS

Fragmentation is a common type of ablation of meteoroids. Its inclusio n into the theory used in processing observed data can then yield more accurate parameters of the train plasma and of meteoroids themselves. Using radars, principal information can be obtained from Fresnel char acteristics if studying the radio waves scattered from ionized trains left by meteoroids in the Earth's atmosphere. Fragmentation is known t o be responsible for rather irregular characteristics. The work deals with the Fresnel characteristics of signals reflected from meteor trai ns of underdense type when taking into consideration various kinds of physical processes. Because it is important to know if fragmentation i s the only process which could be responsible for a specific type of o bserved Fresnel characteristics, we compare such characteristics with the characteristics produced by the complex ion composition, regular a tmospheric wind field, photochemical processes, electron thermalizatio n and random position of the reflecting point within the ionization cu rve, and we show that the considered effects cannot be an alternative to the fragmentation.