The coughing pulsar magnetosphere

Polar magnetospheric gaps consume a fraction of the electric potential that develops across open field lines. This effect modifies significantly the structure of the axisymmetric pulsar magnetosphere. We present numerical steady-state solutions for various values of the gap potential. We show that a charge starved magnetosphere contains significantly less electric current than one with freely available electric charges. As a result, electromagnetic neutron star braking becomes inefficient. We argue that the magnetosphere may spontaneously rearrange itself to a lower energy configuration through a dramatic release of electromagnetic field energy and magnetic flux. Our results might be relevant in understanding the recent December 27, 2004 burst observed in SGR 1806-20