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SUMMARY:Helicity\, Reconnection and Seifert Surfaces - De Witt Sumners (Fl
 orida State University)
DTSTART:20170922T084000Z
DTEND:20170922T092000Z
UID:TALK80641@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:<span>Co-author: Renzo Ricca (University of Milano-Bicocca)<br
 ></span><br>Reconnection is a fundamental event in many areas of science\,
  from the interaction of vortices in classical and quantum fluids\, and ma
 gnetic flux tubes in magnetohydrodynamics and plasma physics\, to recombin
 ation in polymer physics and DNA biology. By using fundamental results in 
 topological fluid mechanics\, the total helicity of a linked configuration
  of flux tubes can be calculated in terms of linking\, writhe and twist co
 ntributions. We prove that writhe helicity is conserved under anti-paralle
 l reconnection [1]. We discuss the Seifert framing (isophase surfaces in G
 PE models) for a link. We give necessary and sufficient conditions for the
  existence of a Seifert surface for a framed link. We give a rigorous topo
 logical proof of the result that total helicity is zero for linked vortice
 s with Seifert framing. We will discuss parallels between the links in the
  Belusov-Zhabotinsky reaction and links in fluid dynamics. This is joint w
 ork with Renzo Ricca.<br><span><br>[1] Laing\, C.E.\, Ricca\, R.L. & Sumne
 rs\, De W. L. (2015) Conservation of writhe helicity under anti-parallel r
 econnection. Nature Sci. Rep. 5\, 9224.</span>
LOCATION:Seminar Room 1\, Newton Institute
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