  We discuss the processes of brane bubble nucleation induced by the external
branes. The quasiclassical solution for the nucleation by the single external
brane has been found in the case when the brane junctions are possible.
Exponential factor in the production rate has been calculated. The process
induced by the fundamental or D string in the background of two D3 branes is
analyzed and its interpretation from the D3 worldvolume theory viewpoint is
described.
