The observed characteristics of radio-echoes from overdense meteor trains

摘要: Abstract Observational data relating to the duration of radio-echoes from overdense meteor trains are presented and discussed, with particular reference differences between daytime night-time conditions. Experimental distributions echo-duration for different showers observed at various radio frequencies have been collected several sources. When interpreted in terms distribution theory (which, as developed here, represents an important revision previous theories) these shown be consistent assumption that free electrons removed by apparent three-body attachment mechanism, a rate which is approximately three times higher night than during day. The absolute rates emerge this analysis depend on exact ionization model adopted, but most probable range models our values found lower those obtained other workers order magnitude. echoes bright meteors associated Quadrantid shower has increase considerably some 30 min after sunrise region. This phenomenon decrease mean echoes. results indicate deionization particularly rapid below ~80 km night, may no longer appear It echo characteristics cannot satisfactorily explained well-known processes direct recombination or simple atmospheric molecules, indicating much more complex ion-chemistry required.