ATS-6 - UCLA fluxgate magnetometer

A summary of the design of the University of California at Los Angeles' fluxgate magnetometer is presented. Instrument noise in the bandwidth 0.001 to 1.0 Hz is of order 85 m gamma. The DC field of the spacecraft transverse to the earth-pointing axis is 1.0 + or - 21 gamma in the X direction and -2.4 + or - 1.3 gamma in the Y direction. The spacecraft field parallel to this axis is less than 5 gamma. The small spacecraft field has made possible studies of the macroscopic field not previously possible at synchronous orbit. At the 96 W longitude of Applications Technology Satellite-6 (ATS-6), the earth's field is typically inclined 30 deg to the dipole axis at local noon. Most perturbations of the field are due to substorms. These consist of a rotation in the meridian to a more radial field followed by a subsequent rotation back. The rotation back is normally accompanied by transient variations in the azimuthal field. The exact timing of these perturbations is a function of satellite location and the details of substorm development.