Exotic dense matter states pumped by relativistic laser plasma in the radiation dominant regime

TL;DR

This paper demonstrates the formation of exotic hollow atom states in high-energy density plasma using conventional optical lasers in the radiation dominant regime, expanding potential applications in astrophysics, material science, and radiography.

Contribution

It shows that hollow atom states can be generated by optical lasers approaching the radiation dominant regime, previously achievable mainly with free-electron lasers.

Findings

Exotic hollow atom states can be produced with conventional optical lasers.

Laser-produced plasma can serve as an ultra-bright X-ray source.

Potential applications include astrophysics, biological imaging, and material science.

Abstract

The properties of high energy density plasma are under increasing scrutiny in recent years due to their importance to our understanding of stellar interiors, the cores of giant planets$^{1}$, and the properties of hot plasma in inertial confinement fusion devices$^2$. When matter is heated by X-rays, electrons in the inner shells are ionized before the valence electrons. Ionization from the inside out creates atoms or ions with empty internal electron shells, which are known as hollow atoms (or ions)$^{3,4,5}$. Recent advances in free-electron laser (FEL) technology$^{6,7,8,9}$ have made possible the creation of condensed matter consisting predominantly of hollow atoms. In this Letter, we demonstrate that such exotic states of matter, which are very far from equilibrium, can also be formed by more conventional optical laser technology when the laser intensity approaches the radiation dominant regime$^{10}$. Such photon-dominated systems are relevant to studies of photoionized plasmas found in active galactic nuclei and X-ray binaries$^{11}$. Our results promote laser-produced plasma as a unique ultra-bright x-ray source for future studies of matter in extreme conditions as well as for radiography of biological systems and for material science studies$^{12,13,14,15}$.