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

Abstract

The short review on the possible applications of the hollow ion spectra for the diagnostics of the high-temperature plasma created by intensive laser and particle beams is presented. Because of the hollow ion spectra features are defined mainly by the mechanisms of their excitation, we consider the various types of the high-temperature plasma where different excitation processes are important. It is shown that like ordinary spectral lines, spectra of the hollow ions offer considerable diagnostic opportunities. At the present time, hollow ion spectra are used mainly to investigate plasma heated by X-ray radiation, but the hollow ions must be generated when plasma is heated by fast heavy ion beams too. In this case, the resultant substance state will be also characterized by solid-state density, and some spatial regions of targets will have relatively low temperatures, i.e., will be a nonideal plasma. It is emphasized that hollow ion spectra are promising diagnostic tool for both nonideal plasma and warm dense matter.

P3: An installation for high-energy density plasma physics and ultra-high intensity laser–matter interaction at ELI-Beamlines

“…The optically thin spectra of HI are diagnostically very important, as they originate from inner shell transitions which are weakly affected by coupling effects of the plasma environment [165]. Despite their capability of providing information on non-LTE plasmas, hot electron production, and transient, opacity and radiative effects in interaction experiments with PW lasers [166], the theory of HI emission is not fully understood yet.…”

Triple-core-hole states produced in the interaction of solid-state density plasmas with a relativistic femtosecond optical laser

“…Atoms with inner-shell vacancies such as single- and double-core-hole (SCH/DCH) states have been produced and observed by different methods such as collisions with highly charged ions and electron beams 1 – 4 , interaction with synchrotron radiation 5 – 7 and laser beams such as ultra-intense ultrafast x-ray free electron laser (XFEL) 8 – 13 and intense optical lasers 14 – 20 . These exotic atomic states contain rich information of the surrounding environment and can be helpful in many research fields such as chemical analysis 21 – 23 , x-ray atomic laser 24 , 25 and warm and hot dense matter 26 – 29 .…”

Evidence of high-n hollow-ion emission from Si ions pumped by ultraintense x-rays from relativistic laser plasma

“…This is in part due to the increasing availability of such radiation-generating sources as XFELs [1][2][3][4][5] and next-generation petawatt laser facilities that can generate high-intensity x-ray fields [6]. These experimental platforms have been used to create novel states of matter with empty inner sub-shells [2][3][4][5][6][7][8][9][10][11], explore the phenomena of continuum lowering [12] and of saturable absorption [13],…”

“…Such investigations, as well as complementary simulations (for example, [15,16]) help our understanding of high-energy density plasmas of importance in astrophysics [17][18][19], inertial confinement fusion [20], and the bright x-ray sources are also of use in biological imaging and in materials science [21]. Recent reviews [10,11,22] have explored in detail the mechanisms of hollow-ion emission in a variety of experimental contexts.…”