We present an indirect method to diagnose the electron beam behaviors and bubble
dynamic evolution in a laser-wakefield accelerator. Four kinds of typical bubble dynamic
evolution and, hence, electron beam behaviors observed in Particle-In-Cell simulations are
identified correspondingly by simultaneous measurement of distinct angular distributions of
the betatron radiation and electron beam energy spectra in experiment. The reconstruction
of the bubble evolution may shed light on finding an effective way to better generate high …