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. Speci"cally, we study the e!ects of extremely high "elds on ion electronic structure. These high "elds are achieved in either of two ways: (1) by the "eld of unscreened ion charges in a plasma (&109 V/cm), which result in strongly coupled e!ects such as continuum lowering, line broadening and line-merging, or (2) by the high electromagnetic "eld of an intense laser (&1011 V/cm), which results in the formation of laser satellites around forbidden X-ray lines. ( 2000 Elsevier Science Ltd. All rights reserved.