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SUMMARY:Solitons and Breathers on Quantized Superfluid Vortices - Salman\,
  H (University of East Anglia)
DTSTART:20121205T133000Z
DTEND:20121205T135000Z
UID:TALK41866@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:It is well known that quantized superfluid vortices can suppor
 t excitations in the form of helical Kelvin waves. These Kelvin waves play
  an important role in the dynamics of these vortices and their interaction
 s are believed to be the key mechanism for transferring energy in the ultr
 a low temperature regime of superfluid turbulence in $^4$He. Kelvin waves 
 can be ascribed to low amplitude excitations on vortex filaments. In this 
 talk I will show that larger amplitude excitations of the vortices can be 
 attributed to solitons propagating along the vortex filament. I will revie
 w the different class of soliton solutions that can arise as determined an
 alytically from a simplified vortex model based on the localized induction
  approximation. I will show\, through numerical simulations\, that these s
 olutions persist even in more realistic models based on a vortex filament 
 model and the Gross-Pitaevskii equation. As a generalisation of these soli
 ton solutions\, I also consider the breathe r solutions on a vortex filame
 nt and illustrate how\, under certain conditions\, large amplitude excitat
 ions that are localized in space and time can emerge from lower amplitude 
 Kelvin wave like excitations. The results presented are quite generic and 
 are believed to be relevant to a wide class of systems ranging from classi
 cal to superfluid vortices. I will also interpret our results on these non
 linear vortex excitations in the context of the cross-over regime of scale
 s in superfluid turbulence.\n\n
LOCATION:Seminar Room 1\, Newton Institute
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