Transient magnetic field formulation for solid source conductors

The formulation for the azimuthal component of the magnetic vector potential for axisymmetric magnetostatic applications is well known. However for transient magnetic fields with solid source conductors and eddy currents the formulation has to be revised. A variable transformation is introduced to remove the singularity from the numerical scheme. The numerical error cannot accumulate and is put instead to the postprocessing at every time step.

A Small-Sized and Battery-Supplied Data Acquisition System for the Electromagnetic Launcher to Measure Pulsed Magnetic Fields

In rail-gun launchers, the main current is pulsed and can reach up to several MA. The width of the pulse is about 2 - 4ms. When pulsed currents are supplied from the pulse power, it will generate a large transient magnetic field around the armature. Meanwhile, the armature will be accelerated up to 2km/s by a large electromagnetic force. In order to research the features of the fields around contact surfaces between rails and the armature, it needs to use a small-sized and battery-supplied data acquisition system to measure pulsed magnetic fields. The B-dot probe acts as a sensor to acquire the transient magnetic fields. All data will be stored in a SD card. The armature and SD card will be caught and fetched back after the launching. The system would be suitable and useful for the electromagnetic launcher design.

Weak Transient Magnetic Fields Detecting in Thermomagnetic Effect Study of Polymer Material Deformations

A self-developed magnetic detector is presented, which is made up with 64 Hall sensors assembled as an 8×8 serried array in a 50×50mm quadrate circuit wafer, to catch a weak transient magnetic field. The disadvantage accompanying with compact design is the sharp rise of sensor’s working temperature due to the power consumed is on increasing. An approach in which the 64 Hall elements are connected as a three dimensional magnetic-pixel matrix and are driven by dynamic power is presented. The homologous hardware correction illustrative diagram is provided, including its measuring principle and multivariate calibration technique. The experimental results indicated that the proposed method is a beneficial exploration for sensor power supply.