First results of the HIA instrument on the Tan Ce 1 Double Star near Equatorial Spacecraft

On December 29, 2003, the Chinese spacecraft Tan Ce 1 (TC 1), first component of the Double Star mission, has been launched with success in a low latitude orbit. In the frame of the scientific cooperation between the Academy of Sciences of China and ESA, several European instruments identical to those developed for the Cluster spacecraft were installed on board this spacecraft. The HIA (Hot Ion Analyzer) instrument on-board TC 1 is an ion spectrometer identical to the HIA sensor of the CIS instrument on-board the 4 Cluster spacecraft. This instrument has been specially adapted for TC 1. It measures the 3D distribution functions of the ions between 5 eV per q and 32 keV per q without mass discrimination. TC 1 is like a fifth Cluster to study the interaction of the solar wind with the magnetosphere and to study the storms and substorms. HIA was commissioned in February 2004. Since this period HIA has done very good measurements in the solar wind, the magnetosheath, the dayside and nightside plasma sheet, the ring current and the radiation belts. We will present the first results in coordination with the CIS Cluster measurements. These include for example ion dispersion structures in the bow shock and ion beams close to the magnetopause.