An attempt to resolve pulsar magnetospheres using interstellar scintillations

Interstellar scintillations of separate pulse components were measured as a test for whether the corresponding emission regions are spatially separated when radiating toward an observer. Pulse components scintillate identically within the errors, implying that the emission regions have transverse separations that are less than or approximately equal to 1000 km. In polar cap models, such separations correspond to a limit on emission altitude of 6 percent of the light-cylinder radius for PSR 0525 + 21. In light cylinder models, the limits require that nonazimuthal velocities of the emission regions must be identical to within a value of the delta v to v ratio that is less than or approximately equal to 0.06 and must be within 3 deg of the radial direction.