Decoupling of corona and core of laser-heated pellets

When a pellet of solid deuterium is heated in vacuum by convergent laser beams, the laser light is absorbed in a tenuous plasma corona surrounding a dense plasma core. If an attempt is made to heat the plasma too quickly, the corona electron temperature can decouple from that of the core, rising to a high value while the core temperature increases very little. This decoupling effect is examined quantitatively, and it is concluded that the effect may be severe for laser light whose wavelength much exceeds one micron.