FGM, fluxgate magnetometer

One of the primary objectives of the Double Star mission is the accurate measurement of the magnetic field vector along the orbits of the two spacecraft. The magnetic field is an essential parameter for the understanding of space plasma processes and is also required for the effective interpretation of data from the other instruments on the spacecraft. The FGM magnetometer experiments on TC-1 and TC-2 consist of two sensors: the outer sensor (OB) is placed at the tip of a 3.1 m long boom and the inner sensor (IB) is 50 cm closer to the spacecraft. Due to a wrong wiring of the solar panels on TC-1, very large magnetic interferences (20-30 nT) occur in the magnetic field measurements. With help of European expertise, the solar array wiring was quickly corrected for TC-2 within a few months in spring 2004 before its launch. Furthermore, the shunting system of the spacecraft solar power system caused sudden changes in the level of interferences. Finally the observations suffered from frequent telemetry errors causing random spikes in the data. With help of dual fluxgate measurements and signal processing technique, the data have been cleaned first from the spikes and then from the solar array disturbances to an accuracy of better than 0.5 nT for most of the time. The cleaning of the data was an effort led by ESA, in collaboration with the PI teams. All FGM datasets are available on the ESA Cluster Science Archive at https://csa.esac.esa.int/ FGM key scientific datasets for TC-1 and TC-2 Dataset ID Dataset content D1_CP_FGM_FULL Magnetic field, full resolution, TC-1 D1_CP_FGM_SPIN Magnetic field, spin resolution, TC-1 D2_CP_FGM_FULL Magnetic field, full resolution, TC-2 D2_CP_FGM_SPIN Magnetic field, spin resolution, TC-2