Text | Pulsars are born with an embryonic ,rigid-body ,rotating super baryon at its center surrounded by dissipative nuclear medium. When the pulsars rotate, there is a continuous loss in their rotational energy. But the energy curve shows glitches, which are caused due to the transition of the super baryon between rotational energy levels. While rotating this core will expel vortices as it transitions, which will then reconnect and dissipate as kelvin waves. The objective of the project is to produce a simulation of quantum vortices and see how they behave in an ambient medium, in the form of rotation, bending and reconnecting with each other, In this case we place a ambient medium inside a cylindrical container and a spherical solid core. We also study how the core plays a role in modifying the dynamics of these vortices by adding perturbations to the surface of the sphere.The code to produce all of this was developed by Andrew Baggaley from School of Mathematics and Statistics, Newcastle University. It includes fortran and MATLAB source files which help perform the calculations and output the simulation respectively. We obtain the state of the superfluid, i.e it's wave function by solving the Gross-Pitaevskii equation. The code allows us to alter the parameters like the trapping potential, the grid points in the domain, initial condition , dimensions of the vortex lattice etc.But this simulation does not focus on the expulsion phase of vortices and also the formation of kelvin waves, it also considers only one superfluid whereas a more accurate simulation demands another superfluid in the boundary layer between the ambient medium and the baryon core. The study is under modification to enable random motion of vortices , and ejection of vortices from central core as dictated by Onsager-Feynman equation, which should then be absorbed by ambient medium and lead to spin up of the outer crust. |
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