RADIO-WAVES IN THE HELIOSPHERE

Solar radio emissions at long wavelengths (wavelengths greater than 10 m or frequencies smaller than 30 MHz) are produced in the upper corona and in the interplanetary medium (the Heliosphere), sometimes at very large distances from the Sun, up to the orbit of Jupiter and beyond. Solar radio emissions are produced by the passage of energetic particles and shock waves; they provide a unique means to detect perturbations originating from the solar activity and to track their progression through the interplanetary medium. Different aspects of current research are presented, essentially based on results of the URAP investigation on ULYSSES.