Interrelation between radio and X-ray signatures of drifting subpulses in pulsars

Aims. We examined a model of partially screened gap region above the polar cap, in which the electron-positron plasma generated by sparking discharges coexists with thermionic flow ejected by the bombardment of the surface beneath these sparks. Our special interest was the polar cap heating rate and the subpulse drifting rate, both phenomena presumably associated with sparks operating at the polar cap. Methods. We investigated correlation between the intrinsic drift rate and polar cap heating rate and found that they are coupled to each other in such a way that the thermal X-ray luminosity L-x from heated polar cap depends only on the observational tertiary subpulse drift periodicity (P) over cap (3). Results. Within our model of partially screened gap we derived the simple formula relating L-x and (P) over cap (3), and showed that it holds for PSRs B0943+10 and B1133+16, which are the only two pulsars in which both L-x and (P) over cap (3) are presently known.