Slide 19 of 59
Notes:
The decay time of the magnetic field is given by the equation shown. The ‘dimension’ in the case of a neutron star is assumed to be the radius of the polar cap where the magnetic field lines are concentrated. This is ~2% of the total surface of the neutron star thus for a radius of 10,000m is about 3000m.
The conductivity, s, can be found from the following:
Ohm’s Law states that j = (1/r) .E
