Highly Local Measurements of Strong Transient Magnetic Fields During Railgun Experiments Using CMR-Based Sensors

The accurate measurement of the magnetic field distribution during electromagnetic launch experiments is an ambitious task. Loop sensors are widely used for detecting the change in magnetic flux. However, this technique is mostly used only for qualitative purposes, e.g., for triggering various devices. This paper deals with the use of another type of high magnetic field sensor based on thin (prim=0.6 MJ, l=3 m, cal=15 mmtimes30 mm). Transient magnetic field profiles with rise times of approximately 50 mus and amplitudes up to 4 T were recorded. The results obtained with the CMR sensors are compared with those of conventional loop sensors. Also, some metrological peculiarities due to high-frequency coupling to the detector circuit are mentioned. The highly local measurements of these CMR sensors were validated by results obtained from 3-D finite element (FE) calculations of the magnetic field distributions