An experiment has been done at the National Ignition Facility (NIF) using a buried layer platform to study the radiative properties of non-local thermodynamic equilibrium (NLTE) gold plasma at an electron temperature of ∼3 keV and an electron density of ∼10$^{21}$cm$^{−3}$. The targets used consisted of a 625 μm diameter, 1900 Å thick dot with two different mixtures of Au and Zn: one at 1:2.25...
Determining plasma opacities requires knowledge of the electronic structure
of many atomic configurations. For dense plasmas, the number of configurations
required to accurately represent the plasma is often intractably large when using
methods that require explicit accounting of each configuration. The supercon-
figuration concept [1] allows one to use a representative atomic structure...
It is now well established that tungsten will be one of the main divertor components of the ITER nuclear fusion reactor. When D-T fusion takes place, very energetic neutrons will strike the walls of the reactor and cause the transmutation of tungsten atoms by irradiation. The primary transmutation products for tungsten are rhenium, osmium and tantalum. In particular, the calculations revealed...
Dielectronic recombination (DR) is the dominant photorecombination channel for Fe XVII in hot astrophysical plasmas, producing strong satellite transitions seen in the 3s – 2p and 3d – 2p line formation channels of X-ray spectra from stellar coronae. Dielectronic resonances also contribute strongly to the collisional excitation of Fe XVII ions. Theoretical calculations of both DR and resonant...
We present specific configuration-average (CA) collisional-modeling calculations of tungsten plasmas at low electron density Ne = 5 1013 cm-3 for electron temperatures in the range 0.8 to 5 keV. These conditions are relevant to current tokamaks. In this temperature range, the modeling of the ionization balance and of the spectra is a long-standing problem.
We discuss here the problem of...
The atomic structure, transition properties, kinetic processes, and emission spectra of tungsten ions are extremely important for diagnosing edge and impurity plasmas in the next-generation magnetic confined fusion reactors (such as ITER). For diagnostics, the accurate atomic data, such as the energy level, radiative transition rate, electron collisional excitation cross section, etc., and...
Oscillating electric fields are found in many kinds of plasmas. In laboratory and fusion plasmas, they are often generated by an external source, such as a laser or a microwave generator. In such plasmas and in astrophysical plasmas, oscillating fields can also be excited by a local fluctuation, and be amplified by a plasma instability, generating non-thermal plasma waves such as Langmuir...
Dielectronic recombination (DR) is a fundamental process in plasma physics, which involves the resonant capture of a free electron by an ion and the subsequent emission of photons or other particles. DR is important in the study of astronomical plasmas, such as those found in stars and the interstellar medium [1]. The study of DR can provide insight into the composition and physical conditions...
In the present work, we calculate and
analyze ionization total, singly differential and
fully differential cross sections for hydrogen
embedded in a weak plasma environment due to
light particle impact. Calculations at the total and
singly differential level, either in terms of the
electron emission energy or the emission angle,
are performed within the framework of the
classical...
Introduction: Breast cancer has become the most prevalent cancer in the world since 2021. The out- of-control growth of breast cells results in breast cancer. The type of breast cancer depends on which cell in the breast becomes cancerous. Due to the high incidence and limitations of surgery, chemotherapy, and radiotherapy including non-selective and incomplete tumor ablation, Non-thermal...
Collisional-radiative calculations can provide reliable emission and opacity spectra if the cross-sections of the various microscopic processes occurring in a dense plasma are accurate. In this work, we focus on electron impact ionization (EII). Since the EII cross-section depends strongly on the ionization energy and since the latter is very sensitive to the plasma environment (« density...
Isomers, or long-lived nuclear excited states, are of significant interest in both fundamental and applied physics. For example, understanding the atomic and electromagnetic processes that lead to nuclear excitation is crucial from the study of nucleosynthesis in astrophysical plasmas to the development of high-density energy storage applications.
This study focuses on the design and...
Synopsis
A cross section dataset has been calculated for electron scattering from the ground and first four excited states of neutral tin using the Relativistic Convergent Close-Coupling method. Integrated cross sections have been produced over a projectile energy range of 0.1 eV to 1000 eV for all major processes. Maxwellian rate coefficients with analytical fits are available for...
Electron impact recombination, (ro-)vibrational, electronic and dissociative excitation of molecular cations:
\begin{equation}
AB^+ + e^- \rightarrow AB^, AB^{} \rightarrow
\begin{cases}
A+B & \
AB^{+} + e^- & \
A+B^++e^-&
\end{cases},
\end{equation}
are in the heart of the molecular reactivity in the cold ionized media [1], being major charged particles destruction...
The study of electron-ion collisions always be a prime area of research as it provides the fundamental understanding of the dynamical behavior of different atomic processes in the high temperature plasma. During the collisions, the electrons can be recombined with ions through different reactions such as electron-impact excitation (EIE), dielectronic recombination (DR) and many more. In EIE...
Detailed, accurate, complete atomic datasets, including energy levels, radiative transition probabilities, excitation and ionisation cross sections and recombination rates, are vital for accurately modelling fusion plasmas. The R-Matrix approach is well known to be one of the most powerful and reliable methods for calculating these atomic parameters.
Recent and ongoing developments of the...
Impurities of the low- and medium-Z elements injected into the fusion reactors are used to control the heat load from the hydrogen plasma. The radiative cooling from the injected impurities depends on the charge state distribution of ions. Radiative recombination and electron-impact ionization define the charge state distribution in the fusion plasma. Nitrogen is one of the elements that...
The plasma divertor for the International Termonuclear Experimental Reactor (ITER) will have target plates made out of tungsten (W) [1]. The inevitable W contamination will emit characteristic radiation that depends on the specific charge state balance, electron temperature and density conditions. Therefore, the respective emission spectra can be used as real-time diagnostics of the fusion...
Iron, the most abundant heavy element in the universe, is essential for spectroscopic studies. X-ray astronomers use the emission lines from highly ionized iron states like Fe XVII to study properties of hot celestial plasmas. These emission lines, which result from atomic processes like electron-impact excitation, dielectronic recombination, resonance excitation, and charge exchange, allow...
Magnetic-field-induced transitions have recently seen an enormous increase in interest. They arise due to the mixing of magnetic sublevels that start to occur in the non-linear region of the Zeeman effect. Especially concerning highly charged ions, the modeling is based on MCDHF calculations that are perturbed by the diagonalization of the full Zeeman interaction matrix [1].
However, this is...
On August 17, 2017, the LIGO-VIRGO collaboration observed a neutron star merger thanks to the first detection of gravitational waves. They also detected an explosion of hot and radioactive matter called a kilonova [1]. In the latter, there are nuclear reactions that form heavy nuclei (heavier than iron) such as lanthanides (Z = 57 – 71) which play a particular role. In fact, given their rich...
In the recent decades, there is an increasing interest in the properties of material under extreme conditions of temperature and density (T-rho). The physical description of stars and planets formation and evolution, controlled fusion experiments and laser-material interaction requires the knowledge of the equation of state, opacity, ionization degree and some other physical quantities in a...
The 2017 observation of the electromagnetic counterpart to the gravitational wave signal GW170817 provided direct evidence that r-process elements are created in neutron-star mergers. The electromagnetic transient, also known as a kilonova, has revealed two distinct ejecta components: one containing heavy r-process material, including lanthanides and potentially actinides, and a second one...
Introduction: The effects of cold plasma, such as antimicrobial, anti-inflammatory, tissue regeneration, cell proliferation, and angiogenesis, have made this technology a therapeutic option for wound healing [1]. These effects are not only related to the treatment duration and type of tissue, but also depend on the plasma configuration, working gas, and plasma distance.
The dielectric...
We present total and energy and angular differential cross sections for single-ionization and single charge exchange in a collision between singly charged lithium and sodium with ground-state helium and nitrogen atoms. For sake of simplicity, the considered collision systems are treated as three-body problems. The helium and nitrogen atomic targets are described within the single active...
Gravitational waves from the neutron star merger GW170817 were detected for the first time in August 2017 [1]. Such an astrophysical event also provokes the ejection of hot and radioactive matter which powers an electromagnetic signal known as kilonova. This first observation also provided evidences that rapid neutron-capture process (or r-process) of nucleosynthesis responsible for heavy...
With enhanced relativistic and quantum electrodynamics (QED) effects and reduced electron correlation at high Z, highly charged ions (HCI) offer a great test-bed to benchmark sophisticated atomic theory. Such ions can be reliably created in an electron beam ion trap (EBIT) by tuning the energy of the electron beam. Atomic spectroscopy of the EBIT plasmas can help explore the structure of...
Strongly coupled plasmas are systems where the average potential interaction energy per particle dominates the average kinetic energy. These varieties of systems occur in diverse physical scenarios: condensed matter systems such as molten salts and liquid metals, charged particles in cryogenic traps, diverse astrophysical systems, two-dimensional semiconductor nanostructures, and dusty...
Electrical discharges in water are a subject of major interest because of both the wide range of potential applications and the complexity of the processes. This topic aimed to provide significant insights to better understand processes involved during a microsecond electrical discharge in water, especially during the propagation and the breakdown phases. Two different approaches were...
Efficient extraction of ions from a pulsed photo-plasma has been a major area of research in the field of laser isotope separation. The dynamics of the process becomes far more complex when the ion-atom collisional effects due to the background atomic beam become significant. In this paper, a Monte-Carlo-based PIC (Particle-In-Cell) model has been presented that incorporates collisions of the...
Radiative and non-radiative decay are both important de-excitation mechanisms of ions. To study these processes, collisions including ions in very high charge states (q ≥ 20) are an ideal playground: When close to a surface, resonant electron transfer leads to a population of high-n shells (with n ~ q [1]), initiating a de-excitation cascade of this - then neutral albeit still highly excited -...
Significant discrepancies relevant to helioseismology between experimental and theoretical photon absorption by plasmas remain unresolved. Interestingly, a new process called transient spatial localization (TSL), where the plasma perturbs the final states in photon ionization processes, ostensibly enhances cross-sections resolving the extant discrepancies. The TSL model, however, is shown to...
Opacity, which describes the extent to which the radiation is absorbed and scattered in the material, is essential in understanding the fundamental physical properties of high-energy-density(HED) and astrophysical plasmas. FLYCHK, a collisional-radiative code, has been used to calculate the opacities of HED plasmas under a wide range of conditions due to the simplicity and availability of the...
A clean and safe energy is in high demand nowadays. The levels of pollution due to the conventional energy resources led in to the highest increase of the global average temperature in its recorded history. The conventional resources for energy production are limited and the aim is to find a solution for alternative energy production.
Between many developed technologies to produce renewable...
Soft X-ray emission spectra from highly charged heavy ions are of particular interest in nuclear fusion research, industrial light source applications as well as basic atomic physics. Though a number of experimental spectra have been recorded so far in tokamaks and electron beam ion traps (EBITs), the available data are still insufficient to complete the atomic number (Z) dependencies for the...
State-of-the-art nanolithography machines work with light in the extreme ultraviolet (EUV) regime. This light is generated by a laser-produced plasma (LPP) of Sn. Apart from the EUV photons, the LPP also emits highly charged Sn ions with up to several tens of keV of energy that may damage plasma-facing surfaces. Therefore, industry uses a buffer gas of H$_2$ to slow these ions. In consecutive...
Optical emission spectroscopy is among the prime plasma diagnostic techniques to realize practically the changes that occurred in spectral intensity, electron temperature, electron number density, and impurity concentration. The optical actinometric technique is applied to investigate the addition of impurities in the argon and helium microwave discharges during the wall conditioning process...
Spectroscopic study of excitation energies and radiative
properties of N-like tungsten
Arun Goyal
Shyam Lal College, Delhi University, Delhi-110032, India
**Synopsis: In present work, fine structure energies and radiative data namely,transition wavelengths, transitions rates, oscillator strengths and line...
Table-top plasma X-ray sources driven by high-peak power (fs) laser sources are of high applicative interest for imaging and material science [1,2] because of their capability to provide hard energetic jitter-free point-source pulsed X-ray sources suitable for phase-contrast imaging or (time-resolved) X-ray diffraction. We thus study the characteristics (mainly here focusing on its size...
The heavy elements with high Z are of potential interest in controlled thermonuclear fusion and astrophysics. Indeed, they could be used in plasma-facing materials such as the divertors in tokamaks or/and could be generated by neutron-induced transmutations of divertor’s materials. So, extensive spectroscopic studies both experimental and theoretical have been performed in the last years in...
Although the nitric oxide (NO) is a minority species in the earth’s ionosphere (at altitude between 83 and 200 km) it exhibits a remarkable variation with altitude, latitude, season and magnetic activities. Therefore, it can be used as a tracer to depict such variations. We studied the impact of energetic electron, at high-latitude E and F Earth’s ionosphere regions, on nitric oxide (NO) to...
The merged-beam rate coefficients of dielectronic and trielectronic recombinations (DR and TR) for Be-like ions have been measured in many experiments. Meanwhile, theoretical data were also calculated with AUTOSTRUCTURE (AS) code for comparison with the measured resonance spectrum. However, TR resonance strengths were generally significantly underestimated by the AS calculations in most cases....
In addition to the ohmic heating of the plasma, toroidal electric field in tokamaks which crosses a critical limit, leads to the acceleration of plasma electrons to relativistic energies. Due to the inability of the tokamak magnetic fields to confine them, these energetic electrons escape from the plasma column and collide with the vacuum chamber wall and the plasma facing components. As a...
Pellet injection is the way to provide fuel replenishment in fusion devices. The technique has been also adopted, and actively studied to establish its variant as methodologies for instability suppression, e.g. ELMs using Li pellet, and protecting inner surface via mitigation by a shattered-pelletinduced radiation. Sometimes, such pellet is produced in a cylindrical shape, corresponding to its...
Measurements of plasma parameters in the core of magnetic fusion devices represent a challenging task. Expected emission of x-ray lines of highly charged ions of W will be used in ITER or DEMO for derivation of electron and ion temperature, plasma rotation and finally the plasma control. In spite of considerable efforts to design the x-ray instruments operating in extreme harsh environment of...
