Io-Jupiter Interaction

The Jupiter decameter radio emission (DAM) represents a unique phenomenon in modern space physics. This circumstance stems from the fact that the occurrence of the intense DAM strongly depends on the orbital position of Jupiter`s satellite Io. Due to the spatial difference of the source region of the DAM and Io it is reasonable that there exist several processes, which influence the generation and contribute to the explanation of the DAM. First, the electromagnetic interaction between the Jovian magnetic field and the conducting ionosphere of Io needs to be considered. This interaction leads to perturbations, which are transferred to the source region along the Jovian magnetic field. At the source region close to Jupiter there exists an energy conversion process in order to sustain the transition from the kinetic energy of the particles to radiation energy of the DAM. The present project is embedded into a corporation of scientists from Austria, Russia, Germany, France, and the USA. This project investigates two aspects of the whole phenomenon and the results should be incorporated into the complete description of the influence of Io on DAM. One aspect concerns the electromagnetic interaction between the satellite and the Jovian magnetic field by means of kinetic theory. In order to obtain as general results as possible, this interaction will be considered as an application to the problem of the motion of a moving conducting body in a hot magnetized plasma. In contrast to the former investigations on this theoretical research topic, the considerations will be carried out within the frame of kinetic theory. The main studies will be connected with the so-called dielectric permittivity tensor, which contains all the information of a plasma in the linear approach. This tensor will be investigated and the perturbations due to the moving conductor will be analyzed. This approach will lead to new results and contribute to the commonly accepted Alfven wings model. Since the problem is treated in a very general way, it will be applicable to any moving conducting body in a hot plasma with an external magnetic field, e.g., the orbital motion of a spacecraft. The second aspect is devoted to the processes in the vicinity of the source region of the DAM, in particular, the excitation of a parallel electric field. Such a parallel electric field is an essential condition for the generation of the DAM. The method used to calculate this electric field is based on the concept of moments of the distribution function in order to examine the fluxes carried by different species of particles. These specific particle contributions are produced by the Io volcanism. The present project represents a continuation of a joint cooperation over many years and, additionally, will provide a top research theme for performing the Ph.D. thesis by Mr. Mag. Daniel Langmayr.