Ricardo Florido

Universidad de Las Palmas de Gran Canaria | ULPGC · Department of Physics

Accurate helium White Dwarf (DB) masses are crucial for understanding the DB masses derived using the spectroscopic and photometric methods are inconsistent. Photometric masses agree better with currently accepted DB evolutionary theories and are mostly consistent across a large range of surface temperatures. Spectroscopic masses rely on untested H...

Magnetization of inertial confinement implosions is a promising means of improving their performance, owing to the potential reduction of energy losses within the target and mitigation of hydrodynamic instabilities. In particular, cylindrical implosions are useful for studying the influence of a magnetic field thanks to their axial symmetry. Here w...

We report on measurements of the ion-electron energy-transfer cross section utilizing low-velocity ion stopping in high-energy-density plasmas at the OMEGA laser facility. These measurements utilize a technique that leverages the close relationship between low-velocity ion stopping and ion-electron equilibration. Shock-driven implosions of capsules...

Investigating the potential benefits of the use of magnetic fields in inertial confinement fusion experiments has given rise to experimental platforms like the Magnetized Liner Inertial Fusion approach at the Z-machine (Sandia National Laboratories) or its laser-driven equivalent at OMEGA (Laboratory for Laser Energetics). Implementing these platfo...

Magnetization of inertial confinement implosions is a promising means of improving their performance, owing to the potential reduction of energy losses within the target and mitigation of hydrodynamic instabilities. In particular, cylindrical implosions are useful for studying the influence of a magnetic field due to their axial symmetry. Here we p...

The potential benefits of the use of magnetic fields in Inertial Confinement Fusion (ICF) experiments have been investigated for several years, and exploring them has given rise to new experimental platforms such as the Magnetized Liner Inertial Fusion (MagLIF) approach at the Z-machine, or its laser-driven equivalent at the OMEGA 60 laser. Impleme...

We present the design and first results of a novel all-optical platform to magnetize laser-driven cylindrical implosions at the OMEGA facility. The cylindrical targets are filled with Ar-doped D2 gas and are symmetrically imploded using a 40-beam 15 kJ, 1.5 ns laser drive. We simulated the platform with 2-D numerical simulations using the MHD codes...

We present a comprehensive simulation study of magnetized cylindrical implosions of Ar-doped D2-filled targets at OMEGA using a 15 kJ, 1.5 ns laser drive. The plasma dynamics are numerically investigated in 1-D with the MHD code GORGON (the analysis of 2-dimensional simulations is ongoing and will be presented soon), which, for a seed B-field betwe...

We report on the first accurate validation of low-Z ion-stopping formalisms in the regime ranging from low-velocity ion stopping—through the Bragg peak—to high-velocity ion stopping in well-characterized high-energy-density plasmas. These measurements were executed at electron temperatures and number densities in the range of 1.4–2.8 keV and 4×1023...

Classical molecular dynamics simulations of hydrogen plasmas have been performed with an emphasis on the analysis of the equilibration process. The theoretical basis of the simulation model as well as numerically relevant aspects, such as the proper choice and definition of simulation units, are discussed in detail, thus proving a thorough implemen...

Powerful laser-plasma processes are explored to generate discharge currents of a few $100\,$kA in coil targets, yielding magnetostatic fields (B-fields) in excess of $0.5\,$kT. The quasi-static currents are provided from hot electron ejection from the laser-irradiated surface. According to our model, describing qualitatively the evolution of the di...

Local-thermodynamic-equilibrium (LTE) K-shell spectroscopy is a common tool to diagnose electron density, ne, and electron temperature, Te, of high-energy-density (HED) plasmas. Knowing the accuracy of such diagnostics is important to provide quantitative conclusions of many HED-plasma research efforts. For example, Fe opacities were recently measu...

An assessment of transient effects on the atomic kinetics of argon tracers in inertial confinement fusion implosion cores is carried out. The focus is on typical electron temperature and density conditions achieved in high-and low-adiabat, and shock-ignition implosion experiments performed at the OMEGA laser facility (Laboratory for Laser Energetic...

Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multi-monochromatic x-ray imager (MMI) is an attractive diagnostic for this purpose. The MMI records the spectral signature from an ICF implosion core with time resolution, 2-D space resolution, and spectral resolution. While narrow-band...

Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multi-monochromatic x-ray imager, MMI, records the spectral signature from an ICF implosion core with time resolution, 2D spatial resolution and spectral resolution. While narrow-band images and 2D space-resolved spectra from the MMI data...

Time-resolved temperature and density conditions in the core of shock-ignition implosions have been determined for the first time. The diagnostic method relies on the observation, with a streaked crystal spectrometer, of the signature of an Ar tracer added to the deuterium gas fill. The data analysis confirms the importance of the shell attenuation...

Wire-array two-component Z-pinch plasmas containing Al and other elements were studied experimentally and the observations interpreted with the help of theoretical modeling. Special attention was given to achieving reproducible implosions. Cascading implosions in star wire arrays mix components during the implosion phase and implosion dynamics were...

Two-dimensional space-resolved temperature and density images of an inertial confinement fusion (ICF) implosion core have been diagnosed for the first time. Argon-doped, direct-drive ICF experiments were performed at the Omega Laser Facility and a collection of two-dimensional space-resolved spectra were obtained from an array of gated, spectrally...

Radiative shock waves play a pivotal role in the transport energy into the stellar medium. This fact has led to many efforts to scale the astrophysical phenomena to accessible laboratory conditions and their study has been highlighted as an area requiring further experimental investigations. Low density material with high atomic mass is suitable to...

In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending o...

The Atomic Physics Group at the Institute of Nuclear Fusion (DENIM) in Spain has accumulated experience over the years in developing a collection of computational models and tools for determining some relevant microscopic properties of, mainly, ICF and laser-produced plasmas in a variety of conditions. In this work several applications of those mod...

Fundamental research and modelling in plasma atomic physics continue to be essential for providing basic understanding of many different topics relevant to high-energy-density plasmas. The Atomic Physics Group at the Institute of Nuclear Fusion has accumulated experience over the years in developing a collection of computational models and tools fo...

A spectroscopic method has been developed to extract the three-dimentional spatial structure (i.e., spatial distribution of electron temperature and density) of inertial confinement fusion implosion cores based on the analysis of space-resolved spectra from a tracer element recorded along three quasi-orthogonal lines of sight. We discuss a spectral...

In this work several relevant parameters and properties for krypton and xenon plasmas are analyzed, such as, for example, the average ionization, the plasma thermodynamic regimes, the radiative power losses and the mean opacities. This analysis is performed in a range of density and temperature typically found in laboratory experiments to generate...

Xenon is a common element employed, for example, as impurity in magnetically confined plasmas or the medium in which radiative shocks propagate in laboratory astrophysics. In both situations, it is required the knowledge of plasma parameters such as the average ionization, the charge state distribution, the atomic level populations and the radiativ...

This article has been published in the Early View section of www.cpp-journal.org: 19 APR 2011 with the DOI number: 10.1002/ctpp.201000104 and is equal to the article: Determination and Analysis of the Thermodynamic Regimes of Xenon Plasmas (pages 863–876) R. Rodriguez, J.M. Gil, R. Florido, J.G. Rubiano, M.A. Mendoza, P. Martel, and E. Minguez publ...

A new Relativistic Screened Hydrogenic Model has been developed to calculate atomic data needed to compute the optical and thermodynamic properties of high energy density plasmas. The model is based on a new set of universal screening constants, including nlj-splitting that has been obtained by fitting to a large database of ionization potentials a...

Radiative shock waves play a pivotal role in the transport energy into the stellar medium. This fact has led to many efforts to scale the astrophysical phenomena to accessible laboratory conditions and their study has been highlighted as an area requiring further experimental investigations. Low density material with high atomic mass is suitable to...

A spectroscopic method is discussed to measure core and compressed-shell conditions in thick-wall plastic-shell implosions filled with deuterium and a tracer amount of argon. Simultaneous observation over a broad photon energy range of the argon line emission and the attenuation and self-emission effects of the compressed shell confining the core y...

We discuss the processing of data recorded with multimonochromatic x-ray imagers (MMI) in inertial confinement fusion experiments. The MMI records hundreds of gated, spectrally resolved images that can be used to unravel the spatial structure of the implosion core. In particular, we present a new method to determine the centers in all the array of...

We discuss the processing of spectrally-resolved core images from argon-doped, deuterium-filled OMEGA direct-drive implosions. Spectrally-resolved images were recorded by a DDMMI instrument which consists of a pinhole array, a multi-layer Bragg mirror, and an x-ray framing camera with micro-channel plates. The pinhole array creates a large number o...

We present results from the spectral postprocessing of a one-dimensional hydrodynamic simulation of an argon-doped, warm-shell shock-ignition implosion with a detailed atomic and radiation physics model. The argon tracer is added to the deuterium filling in the core for diagnostic purposes. Spectral features in the emergent intensity distribution i...

In this work we present a set of atomic models (called ABAKO/RAPCAL), and its validation with experiments and with other NLTE models. We consider that our code permits the diagnosis and the determination of opacity data. A review of calculations and simulations for the validation of this set is presented.As an interesting product of these calculati...

In this work we obtain analytical expressions for the radiative opacity of several low Z plasmas (He, Li, Be, and B) in a wide range of temperatures and densities. These formulas are obtained by fitting the proposed expression to mean opacities data calculated by using the code ABAKO/ RAPCAL. This code computes the radiative properties of plasmas,...

Non-local thermodynamic equilibrium (NLTE) conditions are universal in laboratory and astrophysical plasmas and, for this reason, the theory of NLTE plas-mas is nowadays a very active subject. The populations of atomic levels and radiative properties are essential magnitudes in the study of these plasmas and the calculation of those properties reli...

We discuss calculations of synthetic spectra for the interpretation and analysis of K-shell and bound-free emission from argon-doped deuterium-filled OMEGA direct-drive implosion cores. The spectra are computed using a model that considers collisional-radiative atomic kinetics, continuum-lowering, detailed Stark-broadened line shapes, line overlapp...

Radiative properties of hot dense plasmas remain a subject of current interest since they play an important role in inertial confinement fusion (ICF) research, as well as in studies on stellar physics. In particular, the understanding of ICF plasmas requires emissivities and opacities for both hydro-simulations and diagnostics. Nevertheless, the ac...

An analysis of the influence of the atomic description and the configuration interaction effects in the calculation of plasma average ionization and relevant plasma radiative properties such as the spectrally resolved emissivities and opacities, radiative power losses and mean opacities, is performed. Since the larger effects of the configuration i...

We discuss the observation of spectrally resolved image data from argon-doped, deuterium-filled OMEGA direct-drive implosions. A titanium-doped tracer layer is also embedded in the plastic shell. The image data were recorded simultaneously along three quasi-orthogonal lines of sight (LOS) using three identical, gated Direct-Drive Multi-Monochromati...

We discuss the observation and spectroscopic analysis of argon K-shell x-ray line spectra from argon-doped deuterium-filled OMEGA direct-drive shock-ignition implosions based on data recorded with streaked crystal spectrometers. The argon line spectrum is primarily emitted at the collapse of the implosion thus providing a spectroscopic signature of...

In a simple previous analysis the ratio of local emission profiles of carbon impurities (C^4+ at 227.1 nm and C^5+ at 529.0 nm) measured from TJ-II plasmas was found to have a significant dependence of neutral density profile. Hence, the aim of this work is to have a better theoretical understanding of this system and finally validate or discard th...

We discuss the modeling of population kinetics of nonequilibrium steady-state plasmas using a collisional-radiative model and code based on analytical rates (ABAKO). ABAKO can be applied to low-to-high Z ions for a wide range of laboratory plasma conditions: coronal, local thermodynamic equilibrium or nonlocal thermodynamic equilibrium, and optical...

A code has been developed for calculating opacities of hot dense plasmas. This uses the average atom model and a new relativistic screened-hydrogenic model to calculate energy levels and occupation numbers in order to obtain opacities with contributions from bound-bound, bound-free, free-free and scattering processes under LTE conditions.

We discuss the observation and data analysis of argon K-shell line spectra from argon-doped deuterium-filled OMEGA direct-drive implosion cores based on data recorded with two streaked crystal spectrometers. The targets were 870 microm in diameter, 27 microm wall thickness plastic shells filled with 20 atm of deuterium gas, and a tracer amount of a...

Detailed analysis of x-ray narrow-band images from argon-doped deuterium-filled inertial confinement fusion implosion experiments yields information about the temperature spatial structure in the core at the collapse of the implosion. We discuss the analysis of direct-drive implosion experiments at OMEGA, in which multiple narrow-band images were r...

Partially-space-integrated spectra (PSIS) can be extracted from spectrally-resolved core image data recorded in implosion experiments using a gated multi-monochromatic x-ray imager (MMI). To this end, a portion of the core image is selected and spatially-integrated across the array of core images recorded by MMI. The result is a time-resolved spect...

This work describes ABAKO∕RAPCAL, a flexible computational package for the study of population kinetics and radiative properties of non‐equilibrium plasmas in a wide range of physical conditions. The code was developed looking for an optimal compromise between accuracy and computational cost. ABAKO∕RAPCAL assembles a set of simple analytical models...

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...

Radiative properties are fundamental for plasma diagnostics and hydro-simulations. For this reason, there is a high interest in their determination and they are a current topic of investigation both in astrophysics and inertial fusion confinement research. In this work a flexible computation package for calculating radiative properties for low and...

The purpose of this work is to calculate the multifrequential and mean opacity of optically thin carbon plasmas in a wide range of density and temperature, where corona equilibrium, local thermodynamic equilibrium and non-local thermodynamic equilibrium regimes are present.

In this work we present ABAKO, a new computational code based on analytical models and developed to study the population kinetics of steady-state plasmas. The tool ABAKO can be applied to low-to-high Z ions under a wide range of laboratory plasma conditions: coronal, LTE or NLTE, optically thin or thick plasmas. Autoionizing states are explicitly i...

The accurate computation of radiative opacities is basic in the ICF target physics analysis, in which the radiation is an important feature to determine in detail. For this reason, accurate analytical formulas for giving mean opacities versus temperature and density of the plasma seem to be a useful tool. In this work we analyse some analytical exp...

In this work it is accomplished a study of radiative properties of aluminium plasmas. It is analyzed the calculation of spectrally resolved and mean opacities both under NLTE and LTE approaches. Furthermore, the effect of the re-absorption of the radiation in these magnitudes is also examined. The calculations were performed into the detailed-level...

In this work is accomplished the determination of the corona, local and non-local thermodynamic equilibrium regimes for optically thin carbon plasmas in steady state, in terms of the plasma density and temperature using the ABAKO code. The determination is made through the analysis of the plasma average ionization and ion and level populations. The...

We discuss the observation and data analysis of K-shell line spectra from argon-doped deuterium-filled OMEGA direct-drive low-adiabat implosions based on data recorded with streaked crystal spectrometers. The argon line spectrum is primarily emitted at the collapse of the implosion thus providing a spectroscopic diagnostic of core implosion conditi...

In this work we analyze the behavior of Pl anck and Rosseland mean opacites of carbon plasmas in a wide range of temperature and densities to propose si mple analytical expressions for these quantities. Carbon is one of the most interesting elem ents under investigation, since it is likely to be a major plasma-facing wall component in ITER, and it...

In several research fields of current interest such as astrophysics or inertial fusion confinement the knowledge of the interactions between the photons and the plasma particles, i.e. plasma radiative properties, result essential. Thus, for example, the understanding of these plasmas requires properties such as emissivities and opacities both for h...

Photoionization process is a subject of special importance in many areas of physics. Numerical methods must be used in order to obtain photoionization cross-sections for non-hydrogenic levels. The atomic data required to calculate them is huge and self-consistent calculations increase computing time considerably, overall when we are studying plasma...

In this work, the effect of the screening due to plasma surrounding in the atomic magnitudes of non-hydrogenic ions immersed in strongly coupled plasmas is analysed. The atomic magnitudes are evaluated in the relativistic detailed configuration accounting approach making use of a central analytical potential developed to model many-electron ions, w...

We review the critical results of the 4th Non-LTE Code Comparison Workshop held in December 2005. To test the NLTE population kinetics codes, both steady-state and time-dependent cases for C, Ar, Fe, Sn, Xe, and Au plasmas were selected for detailed comparisons. Additional features such as the effects of non-Maxwellian free electrons, the influence...