Production of exotic states of matter with the use of X-rays generated by focusing a petawatt laser pulse onto a solid target

The possibility is discussed of using optical laser radiation with an intensity of $>10^{20}~$W cm$^{-2}$ to create an ultraintense X-ray source capable of producing polychromatic radiation with a power flux of $10^{19}~$W cm$^{-2}$ or higher. X-ray radiation of so high an intensity permits not only transforming a condensed matter of the target into a plasma state but also obtaining an exotic plasma state with a high density of hollow ions. Currently not yet in wide use and available in only a few laboratories in the world, lasers with a radiation intensity of about $10^{20}~$W cm$^{-2}$ are more compact and less expensive than free-electron X-ray lasers or lasers used for the indirect heating of fusion targets. The source under discussion can produce by far higher X-ray intensities than plasma X-ray lasers of a similar scale.