Magnetically Induced Stress Waves in a Conducting Solid—Theory and Experiment

The induction of stress waves by transient magnetic fields has been examined analytically for a conducting half space and experimentally for a cylindrical rod. The analytical model predicts both a body force generated compressional wave and a thermoelastic stress wave. The model shows the magnetic, temperature, and stress fields in the half space for various times after a prescribed magnetic field is applied at the boundary. In the experiment a transient, radial, magnetic field (up to 15 kilogauss) was applied to the end of a copper bar. The field was generated by discharging a small capacitor bank through a flat helical coil. The measured compressional stresses obtained in this manner were of the order of the measured magnetic pressure (B²/2μ₀), at the end of the bar.