Numerical Study on the Bombardment Effects of Tungsten by High-Intensity Pulsed Ion Beam

Abstract

In order to study the response of tungsten under high heat load, the nonlinear thermodynamic equations considering the phase transition were established to the tungsten target irradiated by intense pulsed ion beam. Also the equations which describe the thermal stress and the total strain produced by the changed temperature in the material element were built. Numerical method was used to solve the evolutions of the thermal stress field formed in the target, and spatial temporal evolutions of stress field in the tungsten target are obtained. While the ion current density reached 100A/cm2, the surface materials of tungsten target at the beam incident center was melted and then re-solidified due to the heat conduction after the end of a pulse. There exists the gradient of temperature in tungsten, therefore the thermal stress formed. Radial tensile stress is produced within the melting region, meanwhile outside the region compressive stress is formed; the boundary appears on the edge of the melting region. The stresses on the incidental surface of target are larger compared with the internal.