Le 19 mai 2017
De 10h30 à 12h00
Ulrich Geppert
University of Zielona Góra, Poland
For neutron stars to emit radio waves, certain conditions must be met on their polar cap. I will shortly introduce them and present the model of the partially screened gap in which the charges are accelerated to ultra-relativistic energies. Then I will discuss both theoretical and observational evidences that this model may describe correctly the physics at the polar cap of radio pulsars. Simultaneous X-ray and radio observations help to understand the functioning of radio pulsars.
A necessary precondition for the creation of a sufficiently large number of electron/positron pair in the gap above the polar cap is the presence of a very strong and small scale magnetic field structure there. I will present two mechanism that may produce such magnetic spots; thermoelectric field modifications and the Hall drift in the neutron star crust. If the latter one is the relevant process for the creation of magnetic spots, conclusions about the internal magnetic field structure of neutron stars can be drawn.