Orbital Reconstruction of a Bar During Buckling Instability

The resonant structure of the bar at the stage of rapid loss of vertical symmetry, buckling, is investigated. The results obtained agree with the predictions of Quillen et al.’s [1]. During buckling, orbits that circulate with ωz > κ transferred to resonant banana-shaped orbits with ωz = κ and to circulating orbits with ωz less κ, which is accompanied by the formation of the B/PS bulge. It was also found that during buckling, a new family of .at resonant banana-shaped orbits appears, which is responsible for the vertical asymmetry at this stage.