Elisabeth Dalimier

Sorbonne Université-Faculty of Science and Engineering · Laboratoire pour l'Utilisation des Lasers Intenses UMR 7605

Hydrogen atoms, being subjected to a strong magnetic field, exhibit an additional, delocalized potential well at almost a microscopic distance from the nucleus. We studied the influence of the delocalized states of hydrogen atoms on the number of observable hydrogen lines in strongly magnetized plasmas. We show that, for sufficiently large values o...

For relatively strong magnetic fields, hydrogen atoms can have delocalized bound states of almost macroscopic dimensions. Therefore, such states are characterized by a Giant Electric Dipole Moment (GEDM), thus making them very sensitive to an external electric field. We considered the manifestations of the GEDM states in hydrogen spectral line prof...

For relatively strong magnetic fields, hydrogen atoms can have delocalized bound states of almost macroscopic dimensions. We study the influence of the delocalized states of hydrogen atoms on the number of observable hydrogen lines in strongly magnetized plasmas. We show that for sufficiently large values of the pseudomomentum K (K being the integr...

ABSTRACT: There are various methods for spectroscopic diagnostics of electrostatic waves in plasmas for the range of the field strength from about 1 kV/cm to about 1 GV/cm. In the present paper we extend this range down to about 10 V/cm or even lower. We use the fact that for relatively strong magnetic fields, hydrogen atoms can have delocalized bo...

During relativistic laser-plasma interactions, super-strong magnetic fields of the GigaGauss (GG) or even multi-GG range could develop at the surface of the relativistic critical density. We present a new principle for measuring such magnetic fields during relativistic laser-plasma interactions. The principle can be realized by analyzing the profil...

GigaGauss (GG) or even multi-GG magnetic fields are expected to develop during relativistic laser-plasma interactions. In our previous paper we proposed a method for measuring GG magnetic fields based on the phenomenon of Langmuir-wave-cased dips (L-dips) in x-ray line profiles. The L-dips were observed in several experimental spectroscopic studies...

GigaGauss (GG), and even multi-GG magnetic fields are expected to be developed during relativistic laser-plasma interactions. Sub-GG magnetic fields were previously measured by a method using the self-generated harmonics of the laser frequency, and the fact that the magnetized plasma is birefringent and/or optically active depending on the propagat...

Intra-Stark spectroscopy (ISS) is the spectroscopy within the quasi-static Stark profile of a spectral line. The present paper reviews the X-ray ISS-based studies recently advanced for the diagnostics of the relativistic laser-plasma interactions. By improving experiments performed on the Vulcan Petawatt (PW) laser facility at the Rutherford Applet...

Intra-Stark spectroscopy (ISS) is the spectroscopy within the quasistatic Stark profile of a spectral line. The present paper advances the ISS-based study of the relativistic laser-plasma interaction from our previous paper (Oks et al 2017 Opt. Express 25 1958). By improving the experimental conditions and the diagnostics, it provides an in-depth s...

We present X-ray spectroscopic diagnostics in femto-second laser-driven experiments revealing nonlinear phenomena caused by the strong coupling of the laser radiation with the created plasma. Among those nonlinear phenomena, we found the signatures of the Two Plasmon Decay (TPD) instability in a laser-driven CO2 cluster-based plasma by analyzing th...

The processes of photo-detachment or ionization of stable molecules are widely investigated in modern atomic physics. But the present work deals with the calculation of the photo-detachment cross-sections in the case of negative quasi-molecules formed during collisions. The reaction H + H ⁻ + ħω → H + H + e has been taken as an example of bound-fre...

Abstract.We review studies of two kinds of dips in spectral line profiles emitted by plasmas – the dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). There is a principal difference with respect to positions of L-dips and X-dips relative to the unpert...

Transport phenomena in plasmas, such as, e.g., resistivity, can be affected by electrostatic turbulence that frequently occurs in various kinds of laboratory and astrophysical plasmas. Transport phenomena are affected most significantly by a low-frequency electrostatic turbulence—such as, e.g., ion acoustic waves, also known as ionic sound—causing...

Abstract: By analyzing profiles of experimental x-ray spectral lines of Si XIV and Al XIII, we found that both Langmuir and ion acoustic waves developed in plasmas produced via irradiation of thin Si foils by relativistic laser pulses (intensities ~1021 W/cm2). We prove that these waves are due to the parametric decay instability (PDI). This is the...

The interaction of ultra-short, ultra-intense laser pulses with structured targets, such as clusters, exhibits unique features, stemming from the en-hanced absorption of the incident laser light compared to solid targets.Due to the increased absorption, these targets are heated signi cantly,leading to enhanced emission of x-rays in the keV-MeV rang...

It is shown that the production of X-ray emission spectra in the interaction of high-intensity laser radiation with cluster targets may be affected by the bichromatic oscillating electric field arising from the generation of the second harmonic of laser radiation. A technique is proposed for diagnosing harmonic generation in laser - cluster interac...

Abstract. It is shown that the production of X-ray emission spectra in the interaction of high-intensity laser radiation with cluster targets may be affected by the bichromatic oscillating electric field arising from the generation of the second harmonic of laser radiation. A technique is proposed for diagnosing harmonic generation in laser – clust...

We present experiments dealing with a femtosecond laser-driven cluster-based plasma, where by analyzing the nonlinear phenomenon of satellites of spectral lines of Ar XVII, we revealed the nonlinear phenomenon of the generation of the second harmonic of the laser frequency. For performing this analysis we developed new results in the theory of sate...

We present the first study of two kinds of dips (L-dips and X-dips) in spectral lines from femtosecond laser-driven cluster-based plasma. We found that the observed L-dips are caused by Langmuir waves resulting from the two-plasmon decay instability and our experiment constitutes the first observation of the signature of this instability in spectra...

The review covers theoretical and experimental studies of two kinds of dips (local depressions) in spectral line profiles emitted by plasmas: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). Positions of L-dips (relative to the unperturbed wavelength of a spectral line) scale with the electron density Ne roughly as Ne1/2...

Previously we discovered a way for producing not-yet-available fundamental data on charge exchange between multicharged ions, virtually inaccessible by other experimental methods. It was based on the formation of dips (called x-dips) in spectral lines of hydrogen-like ions from laser-produced plasmas. At that time the x-dip phenomenon was considere...

We review studies of two kinds of dips in spectral line profiles emitted by plasmas—dips that have been predicted theoretically and observed experimentally: Langmuir-wave-caused dips (L-dips) and charge-exchange-caused dips (X-dips). There is a principal difference with respect to positions of L-dips and X-dips relative to the unperturbed wavelengt...

The modelling of intense laser interaction with solid targets represents a complicated complex of plasma physics and numerical methods. The presented simulations contribute to a better understanding of plasma-wall interactions by studying the interpenetration and mutual deceleration of two plasma plumes of different materials created on two foil ta...

Jets of energetic ions launched at laser-burnt-through foils represent an efficient tool for investigation of plasma interaction with solid surfaces (plasma-wall interaction, PWI) and for description of transient phenomena occurring close to the walls. Highly charged ions approaching the secondary target interpenetrate the near surface layer, colli...

Directional flows of well-collimated energetic ions produced at laser-burnt-through foils were used to investigate transient phenomena accompanying the plasma interaction with surfaces of solid targets (generally known as plasma-wall interaction, PWI). The plasma jet launched from the rear surface of the 0.8-um-thick Al foil irradiated at oblique l...

In our previous works we predicted theoretically and then discovered experimentally the formation of dips (called x-dips) in spectral lines of hydrogenlike ions from laser-produced plasmas. These dips are caused by charge exchange. At that time the x-dip phenomenon was considered to be possible only in spectral lines of hydrogenic systems: due to t...

Bombardment of solid surfaces by fast ions has been of continuous interest for more than hundred years because of its numerous technical applications [1]. Nowadays, one of the most important fields of interest is connected with studies of the material erosion and migration at plasma-facing components, aiming at a design of the future reactor vessel...

The production of the laser-produced plasma jets at burnt-through low-Z foils was optimized by using three-frame interferometry. When striking secondary targets, these jets of energetic particles represent an efficient tool for the investigation of transient phenomena at surfaces of the plasma-exposed solids. Two sets of precisely measured x-ray sp...

Electrostatic turbulence frequently occurs in various kinds of laboratory and astrophysical plasmas. Transport phenomena are affected most significantly by a low-frequency electrostatic turbulence – such as, e.g., ionic sound. In this case, for computing profiles of spectral lines, emitted by plasma ions, by any appropriate code for diagnostic purp...

Phenomena accompanying interaction of plasma jets with solid materials are systematically studied for their relevance to magnetic and inertial confinement fusion, primarily in the context of a development of future fusion reactors. We report results of experiments carried out on the PALS iodine laser system (one or two beams with pulse energy 5 ÷ 2...

We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Quasi-monochromatic Electric Field (QEF), generated by a high-power short-pulse laser, with a preformed laser-produced plasma. The computation of a synthetic spectrum emitted by such plasmas requires the calculation of the Stark line shape in the presence...

This paper presents an advanced analysis of the spectroscopic signatures of the interaction of a strong oscillating Quasi‐monochromatic Electric Field (QEF), generated by a high‐power short‐pulse laser, with a preformed laser‐produced plasma. The computation of a synthetic spectrum emitted by such plasmas requires the calculation of the Stark line...

Interactions of plasma jets with solid surfaces are extensively studied in context with development of future fusion devices. In experiments carried out on the iodine laser system PALS, the energetic ions were produced at double-foil Al/Mg targets irradiated by one or two counter-propagating laser beams. The plasma jets from the rear surface of the...

The subject of spectral line shapes (SLS), a.k.a. spectral line broadening, which embraces both shapes and shifts of spectral lines, is of both fundamental and practical importance. On the fundamental side, the study of the spectral line profiles reveals the underlying atomic and molecular interactions. On the practical side, the spectral line prof...

The interaction between quasimolecular states produces not only nonadiabatic transitions but also some exotic features in the wings of the spectral profiles emitted by the ions in collision. Although this concept has been fruitfully used for neutral species, some new highlighted experimental data on quasimolecular optical transitions in hot dense p...

The paper presents an advanced analysis of the experimental Al Heβ emission from aluminium plasma created by one ps-laser beam and then subjected to another ps-laser beam when the pulse of the first laser beam was already off. The paper has two equally important goals. The first goal is to present an overview of the general principles of spectrosco...

Theory predicts that the presence of strong single-frequency electric fields results in appearance of satellite or dip structures in X-ray spectral lines emitted from hot dense plasmas. Emission from multicharged ions is measured to determine the effects of laser field. A ps-laser beam was split into two parts: the first created an expanding plasma...

The formalism for the calculation of Stark line profiles in hot dense plasmas submitted to a strong oscillating field is extensively developed. The Liouville space, usually used to deal with the calculation of Stark profiles in dense plasmas, and the Floquet theory, developed to solve time-periodic problems, have been joined together to solve the t...

The quasi-molecular dipole transition moments have been considered analytically within the framework of the two-state approximation with particular emphasis on their roots (zeros) on spectral manifestations of the roots in the adiabatic diabatic limits. The interrelation between the spectral features the non-adiabatic transitions found in [1] has b...

High‐resolution x‐ray spectroscopy is capable of providing complex information on environmental conditions in hot dense plasmas. Benefiting from application of modern spectroscopic methods, we report experiments aiming at identification of different phenomena occurring in laser‐produced plasma. Fine features observed in broadened profiles of the em...

We present a first study of spectroscopic determination of electron temperature and density spatial profiles of aluminum K-shell line emission spectra from laser-shocked aluminum experiments performed at LULI. The radiation emitted by the aluminum plasma was dispersed with an ultra-high resolution spectrograph (lambda/Deltalambda~6000). From the re...

Quasimolecular dipole transition moments have been considered analytically within the framework of the two-state approximation. In the process, the conditions that lead to the occurrence of roots (zeros) for the dipole moments have been carefully studied. The underlying reason for these roots is the orthogonality of the quasimolecular adiabatic sta...

Colliding plasma clouds produced at single-side laser-irradiated double-foil Al/Mg targets represent a well-defined model environment for studying the plasma wall interactions. The front Al foil burns through before the laser pulse maximum, thus the forward-accelerated Al ions are not trapped by the cold Mg foil but collide with the Mg plasma. The...

Precise X-ray spectroscopic investigation of the colliding plasmas produced at single-side laser-irradiated double-foil Al/Mg targets is reported. The spatially resolved, time-integrated line spectra of the Al Lya group were measured using a high-dispersion vertical-geometry Johann spectrometer. The X-ray spectra were evaluated with the multilevel...

Charge exchange in dense plasmas can result in dips in spectral line profiles of hydrogenlike ions of a nuclear charge Z perturbed by fully-stripped ions of a different nuclear charge Z' ≠ Z. These so-called x-dips were described in detail theoretically and discovered experimentally in our previous works. In the theoretical part of the present pape...

The interaction of highly ionized laser-produced plasma jets with gases has been studied with X-ray microscopic methods. Simultaneous high spectral and 2-dimensional spatial resolution provided a detailed topological structure of the counter-propagating plasma and discovered a gas pressure-dependent X-ray emission structure inside the jets of H-lik...

Single (Al) and double (Al/Mg) foils have been irradiated with high energy laser pulses to study the radiative properties during the interaction of highly ionized plasma jets with gases and solids. X‐ray microscopy with two‐dimensional curved Bragg crystals was shown to provide a detailed topological structure with 15 μm resolution and a 5 cm large...

Optical transitions of dense Al laser produced plasmas have been investigated in the out- streaming plasma jet. A str ong emission from line transitions originating from several charge states (Li-like until Ne-like, spectral range 450 - 550 nm) is observed. Spectra simulations which employ ab inito atomic structure calculations have been establishe...

Precise spectroscopic observations of K-shell emission from highly stripped Al ions immersed in dense, constrained-flow laser-produced plasma is reported. By using a vertical dispersion Johann spectrometer, the time-integrated spectra of the Al Heα group were measured with a high spectral and spatial resolution. The complex spectral profiles modifi...