Exotic Dense-Matter States Pumped by a Relativistic Laser Plasma in the Radiation-Dominated Regime

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 .

Diagnostics of warm dense matter by high-resolution X-ray spectroscopy of hollow ions

“…Refluxing of fast electrons, which are responsible for X-ray radiation, between the target's front and rear occurs only in thin foils and vanishes in thick ones. This is the primary reason for the difference of spectra observed by Colgan et al (2013) for the 1. 5 and 20 mkm foils.…”

“…To use the hollow ion spectra for diagnosing of the plasma affected by strong X-ray radiation have been proposed recently in the papers by Vinko et al (2012) and Colgan et al (2013). It should be noted that the properties of such 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 (Chabrier, 2009;Kalman, 2010), and the properties of hot plasma in inertial confinement fusion devices (Atzeni & Meyer-Ter-Vehn, 2004).…”

“…These electrons radiate X-rays via Thomson scattering of the incident and scattered laser light and via Bremsstrahlung through the strong plasma field at the foil surfaces. It was estimated by Colgan et al, (2013) . The proposed concept (see Fig.…”

“…Details of the experiments are described by Colgan et al (2013). Note here that when in such experiments the maximum laser intensity of 3 × 10 20 W/cm 2 was achieved, laser pulse duration was 0.7 ps, and the laser contrast was about 10 9 .…”

Using X-ray spectroscopy of relativistic laser plasma interaction to reveal parametric decay instabilities: a modeling tool for astrophysics

“…High-resolution spectroscopy measurements were performed using a Focusing Spectrometer with Spatial Resolution (FSSR) [34][35][36]. The instrument was equipped with a spherically bent mica crystal with a lattice spacing 2d ~19.94 Å and a radius of curvature of R = 100 mm.…”