Re-thermalisation and flow of laser-produced plasmas in a uniform magnetic field

Detailed time- and spatially-resolved measurements of the electron temperature and plasma density have been made, by means of laser Thomson scattering and other plasma diagnostics, for plasmas produced by laser from a thin wire target in an almost uniform magnetic field ( approximately 1 T). The physical processes involved in plasma/magnetic-field interactions are discussed. It has been found that a part of the translational kinetic energy of the ions in an earlier rapid plasma expansion phase is reconverted into the thermal energy of electrons as the results of the interactions, through the ohmic heating, by a circulating diamagnetic current flowing near the plasma outer boundary, as well as through subsequently shock heating (and additional compression). Also, the plasma expansion along magnetic field lines may be regarded as almost one-dimensional, and the time variation of electron temperature is adiabatic.