X-ray radiation from matter in extreme conditions

We study transient atomic and plasma processes in the new parameter regime of hot dense matter, produced by an intense ultrashort laser pulse. Specifi cally, we study the effects of extremely high fields on ion electronic stru cture. These high fields are achieved in either of two ways: (1) by the fie ld of unscreened ion charges in a plasma(similar to 10(9) V/cm), which resu lt in strongly coupled effects such as continuum lowering, line broadening and line-merging, or (2) by the high electromagnetic field of an intense la ser (similar to 10(11) V/cm), which results in the formation of laser satel lites around forbidden X-ray lines. (C) 2000 Elsevier Science Ltd. All righ ts reserved.