GPS ionospheric imaging during the magnetic storm period of October/November 2003

At the end of October and begin of November 2003 some very high energetic solar eruptions were observed. Large earthward directed coronal mass ejections (CME) caused very perturbed geomagnetic field conditions. The ionospheric response to the interactions between the high energetic solar wind and geomagnetic field, expressed as variations in ionisation, have been monitored using 3-dimensional GPS tomography. For this purpose, integral data of Total Electron Content (TEC) retrieved from groundand space-based (CHAMP satellite) GPS observations are combined to image the electron density distribution in the North polar ionosphere during the storm period. The reconstruction results allow the interpretation of large-scale horizontal and vertical dynamics of the plasma. Variations in electron density are compared with geomagnetic measurements. Local aspects of the influence of energetic particles on the magnetic field and the ionosphere at mid-latitudes are presented using magnetometer measurements and ionospheric D- and E-region registrations of LF reflection height at Collm Observatory, Germany. We also show observations of sudden phase anomalies in LF ranges after enhanced X-ray emissions caused by solar flares. Tomographic results are validated using independent electron density measurements, e.g., from the Langmuir Probe onboard CHAMP