Mesure des champs magnétiques alternatifs et continus dans les plasmas naturels : développement d'un magnétomètre searchcoil à bande étendue.

摘要

Since many years, the CETP has been producing magnetometers to measure alternative magnetic fileds in space (natural plasmas and magnetosphere). Those magnetometers, called searchcoils, are constituted by a ferromagnetic core on which a copper coil is wound. Recently, improvements have been made on the shape of the core to achieve lighter magnetometers, all things being equal. Such magnetometers will be onboard the NASA/THEMIS satellites for example. Due to its physical principle, the searchcoil is not able to measure DC magnetic fields and in scientific space missions, those fields are measured by fluxgates. Magnetic field sensors are widely used in microelectronics but those sensors are far less sensitive than fluxgates (by three orders of magnitude at least). Let us cite Hall effect devices and magnetoresistive sensors. The aim of this work has been to add a DC magnetic sensor, from microelectronics, to the searchcoil and to use the ferromagnetic core of the searchcoil to improve the sensitivity of the DC sensor. The new instrument could provide redundancy on the measurement of the DC magnetic field onboard scientific spacecraft, without any significant increase in mass on the searchcoil.