Source localization of Jupiter's Io dependent radio emissions

The peak frequencies of the Io-dependent part of the Jovian emissions are compared with the surface gyrofrequency determined from Jovian magnetic models in order to localize the source of Jovian radio emissions. The bulk of the Io-controlled emissions was found to be delayed by up to 70 deg of equatorial longitude from the predicted instantaneous position of the Io flux tube, with the L and S emissions both displaying this same unexpected behavior. It is suggested that the source of these emissions is delayed substantially with respect to Io either as an Alfven-wave delay or because of errors in the magnetic field models.