I refer to Noyola Satyal Musielak 2013: "Detection of Exomoons Through Their Modulation of Exoplanetary Radio Emissions"
Abstract: "In the Jupiter-Io system, the moon's motion produces currents along the field lines that connect the moon to the Jupiter's polar regions, where the radio emission is modulated by the currents. Based on this process, we suggest that such modulation of planetary radio emissions may reveal the presence of exomoons around giant planets in exoplanetary systems. The required physical conditions for the modulation are established and used to select potential candidates for exomoon's detection. A cautiously optimistic scenario of possible detection of such exomoons with the Long Wavelength Array (LWA) and the Low-Frequency Array (LOFAR) radio telescopes is provided."