MARFAING , J.

International audience

International audience

In the millihertz range, a single magnetometer can detect magnetic waves in the near-field regime. For such long wavelengths, it can measure the world-wide magnetic-background noise due to any charge displacement on Earth and within its environment. In this frequency band, the normal modes of the Earth's free oscillations exist and when...

One hour before the Sichuan earthquake (Mw=7.9, 2008 May 12, 06:28~TU), amplified, recurrent and well-defined ionosphere excitations at the resonance frequency of the ionosphere floor were observed by the [SQUID]2 system, an ultra low-noise magnetometer with a rejection rate better than 3fT/√Hz over 40~Hz installed within the LSBB underground...

The physical meaning of the azimuth information provided by the ultra low-noise magnetometer instrument [SQUID]2 is analyzed for mesopause and atmosphere electromagnetic signal sources. Consequences for a potential world-wide network of such instruments are evaluated.

International audience

High sensitivity combined with an ultra-low-noise environment [SQUID]2 magnetometer (Superconducting QUantum Interference Device with Shielding QUalified for Ionosphere Detection) allows the observation of Earth–ionosphere couplings. Namely: – identification of a mesopause resonance mode excitable by P waves or by electric field as during the...

Each ground movement on Earth shakes the air column above it. When the acoustic wave reaches the ionosphere floor, charges are temporarily displaced, parallel to the acoustic excitation. An electric current is created giving birth to a magnetic signal. The density difference between ground and air makes the coupling very poor but this is...

International audience

The permanent operation of a 3 axes magnetometer in the LSBB below 550 m of calcite rock is a unique system of magnetic observation: a rejection rate better than 3 fT/Hz over 40 Hz. The observation of magneto-ionosphere responses to wave emissions both at the epicentre and at their arrival at LSBB for earthquakes of magnitude larger than 3 is...

The permanent operation of a 3 axes magnetometer in the LSBB below 550 m of calcite rock is a unique system of magnetic observation: a rejection rate better than 3 fT/Hz over 40 Hz. The observation of magneto-ionosphere responses to wave emissions both at the epicentre and at their arrival at LSBB for earthquakes of magnitude larger than 3 is...