Field-generating thermal instability in laser-heated plasmas

The intense thermal energy flux emanating from the critical layer in laser‐produced plasmas is shown to generate an instability that derives from the magnetic field dependence of the thermal conductivity. This implies that $B$ fields, with their attendant nonuniform heating effects, will occur even in uniformly irradiated spherical pellets or plane slabs. These fields may play a role in attempts to compress pellets for fusion, for example, by being partially trapped and amplified by compression in the interior of a pellet.