Expansion of the spontaneous magnetic field in a plasma produced on a copper target by a CO2 laser

Measurements are presented for the magnetic field B and the uv radiation generated by a plasma produced by irradiation of a copper target by a 4-J 1.7-ns CO2 laser. The dependences of the uv and B intensities on the N2 or the helium background pressure are found to be comparable. There are two phases in the field expansion: diffusion within the photoionized background followed by convection with the laser plasma.