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Abstract

The understanding and the modeling of the Earth's main and crustal magnetic field has greatly advanced with the availability of magnetic field observations from low altitude satellites. Precise data, not modified by external field sources, are crucial for developing the high-quality magnetic field models. To avoid significant contributions from ionospheric currents night side observations during low magnetic activity are chosen. However, especially at CHAMP altitudes ionospheric plasma processes persists throughout the night. It was shown that currents which are driven by the interaction of the plasma with the gravity and magnetic fields and with the thermospheric winds cannot be ignored. Different night side ionospheric current systems have been identified and quantified using the high quality magnetic field observations on board CHAMP. It is particularly important to correct for these currents when field gradients derived from measurements of two closely space satellites are employed in magnetic field modeling. In order to obtain real progress in characterizing the current distribution it is necessary to consider all drivers at the same time and maintain current continuity. Such a task requires employing coupled, self-consistent models of the ionosphere and thermosphere. In the context of ESA's Swarm mission such an integrated study will be performed handling all relevant currents, and predicting the resulting magnetic signals. The model to be employed in this activity is the Coupled Thermosphere/Ionosphere Plasmasphere (CTIP) model. We are going to discuss the study's challenges and its first and expected results.