Fireball fragmentation in the first half of the atmospheric trajectory

We present direct video observations of fragmentation in the first half of the atmospheric trajectory of several fireballs recorded with the Czech part of the European Fireball Network. The fragmentation takes place in the form of wakes. In this work we describe heights, velocities, and sizes of meteoroids, deduced from our Digital Autonomous Fireball Observatories, where these wakes form and disappear, and lengths of wakes from our video records. We compare derived fireball parameters with values derived on the basis of light curve modeling. The aim of the work is to determine the type of fragmentation and propose its possible source. The observed dynamic pressures at these fragmentation points are of the order of 0.01 MPa. Observed flow regimes indicate that the creation of wakes may be triggered by the meteor shock wave. Quasi-continuous fragmentation was determined as the responsible type of fragmentation in the first half of the atmospheric trajectory by our model.