Amplitude-induced critical behavior of quantized vortices in the nonlinear Schrodinger equation

We studied the dynamics of quantized vortices within the context of the generalized nonlinear Schrodinger equation, where a vortex is represented by a coherent circular dip in a homogeneous background field with an intensity beta. We found the critical role of background field on the vortex stability as follows. For beta > beta (c), a vortex is stable with a finite core size, exhibiting a certain critical behavior as beta --> beta (c). For beta < (c), vortices become unstable, turning into an ever-expanding circular kink. (C) 2000 Elsevier Science B.V. All rights reserved.