Extreme Ultra Research Articles

From CO2- to H2O-dominated atmospheres and back

Aims. We investigate the impact of CO2 on the distribution of water on TRAPPIST-1 e, f, and g during the magma ocean stage. These potentially habitable rocky planets are currently the most accessible for astronomical observations. A constraint on the volatile budget during the magma ocean stage is a key link to planet formation and also to judging their habitability. Methods. We expanded the MagmOc module of the VPLanet environment to perform simulations with 1-100 terrestrial oceans (TOs) of H2O with and without CO2 and for albedos 0 and 0.75. The CO2 mass was scaled with initial H2O by a constant factor between 0.1 and 1. Results. The magma ocean state of rocky planets begins with a CO2-dominated atmosphere but can evolve into a H2O dominated state, depending on initial conditions. For less than 10 TO initial H2O, the atmosphere tends to desiccate and the evolution can end with a CO2 dominated atmosphere. Otherwise, the final state is a thick (>1000 bar) H2O-CO2 atmosphere. Complete atmosphere desiccation with less than 10 TO initial H2O can be significantly delayed for TRAPPIST-1 e and f, when H2O has to diffuse through a CO2 atmosphere to reach the upper atmosphere, where photolysis due to extreme ultra violet irradiation occurs. As a consequence of CO2 diffusion-limited water loss, the time of mantle solidification for TRAPPIST-1 e, f, and g can be significantly extended compared to a pure H2O evolution by up to 40 Myrs for an albedo of 0.75 and by up to 200 Mys for an albedo of 0. The addition of CO2 further results in a higher water content in the melt during the magma ocean stage. Thus, more water can be sequestered in the solid mantle. However, only up to 6% of the initial water mass can be stored in the mantle at the end of the magma ocean stage. Our compositional model adjusted for the measured metallicity of TRAPPIST-1 yields for the dry inner planets (b, c, d) an iron fraction of 27 wt%. For TRAPPIST-1 e, this iron fraction would be compatible with a (partially) desiccated evolution scenario and a CO2 atmosphere with surface pressures of a few 100 bar. Conclusions. A comparative study between TRAPPIST-1 e and the inner planets may yield the most insights about formation and evolution scenarios by confronting, respectively, a scenario with a desiccated evolution due to volatile-poor formation and a volatile-rich scenario with extended atmospheric erosion.

Source of the Observed Enhancements in Thermospheric ΣO/N2 During Two Solar Eclipses in 2023

AbstractTwo solar eclipse events in 2023 appeared to produce considerable enhancements in the thermospheric column density ratio of monatomic oxygen to molecular nitrogen (ΣO/N2) as measured by TIMED GUVI. We quantify potential sources for eclipse‐induced ΣO/N2 changes and find that the observed enhancements arise from the ionospheric O+ radiative recombination contribution to the OI 135.6 nm emission from which ΣO/N2 is derived. Variations in the solar Extreme Ultra Violet (EUV) and X‐ray spectrum, due to the difference between the disk spectrum and the coronal spectrum, are also considered but shown to have negligible contributions to the ΣO/N2 enhancements. After accounting for the radiative recombination contribution, we constrain the real thermospheric compositional change to the uncertainty level of the measurements of 5%–10%. These results are valuable for the interpretation of eclipse‐induced ΣO/N2 changes that will further first‐principle model comparisons and lead to a better understanding of the response of the thermosphere to localized variations in solar EUV and X‐ray forcing.

Statistical Properties of Plateau‐Like Turbulence Spectra in the Martian Magnetosheath: MAVEN Observations

AbstractThe Martian magnetosheath provides us with a natural laboratory to study plasma turbulence in the presence of pickup ions and locally generated instabilities. Unlike the typical magnetic‐field spectra with a single spectral scaling at magnetohydrodynamics (MHD) scales in Earth's magnetosheath, the magnetic‐field spectra in the Martian magnetosheath during 4 years of Mars Atmosphere and Volatile EvolutioN observations frequently present an additional spectral break‐point with a shallow slope at MHD scales which we define as a plateau‐like spectral feature. The average occurrence rate of plateau‐like magnetic‐field spectra is 56.6% of our measurement intervals. At moderate pick‐up angles, the occurrence rate increases to a maximum of ∼70.0%. Furthermore, we present a positive correlation with the local ion density and anti‐correlations with the local βi and the solar Extreme Ultra Violet irradiance. A similar occurrence rate in the quasi‐perpendicular and the quasi‐parallel magnetosheath (60.1% vs. 52.9%) indicates that the plateau‐like spectra are more likely formed locally than in the upstream solar wind. Our results suggest that energy injection from pickup ion driven micro‐instabilities, for example, in the form of proton cyclotron waves, has insufficient time to evolve into a fully developed cascade in such a confined space like the Martian magnetosheath.

Modeling Solar Eclipses at Extreme Ultra Violet Wavelengths and the Effects of Nonuniform Eclipse Shadow on the Ionosphere‐Thermosphere System

AbstractThe impacts of solar eclipses on the ionosphere‐thermosphere system particularly the composition, density, and transport are studied using numerical simulation and subsequent model‐data comparison. We introduce a newly developed model of a solar eclipse mask (shadow) at extreme ultraviolet (EUV) wavelengths—PyEclipse—that computes the corresponding shadowing as a function of space, time, and wavelength of the input solar image. The current model includes interfaces for Solar Dynamics Observatory and Geostationary Operational Environmental Satellites EUV telescopes providing solar images at nine different wavelengths. We show the significance of the EUV eclipse shadow spatial variability and that it varies significantly with wavelength owing to the highly variable solar coronal emissions. We demonstrate geometrical differences between the EUV eclipse shadow compared to a geometrically symmetric simplification revealing changes in occultation vary ±20%. The EUV eclipse mask is validated with in situ solar flux measurements by the PRoject for Onboard Autonomy 2/Large Yield Radiometer instrument suite showing the model captures the morphology and amplitudes of transient variability while the modeled gradients are slower. The effects of spatially EUV eclipse masks are investigated with Global Ionosphere Thermosphere Model for the 21 August 2017 eclipse. The results reveal that the modeled EUV eclipse mask, in comparison with the geometrically symmetric approximation, causes changes in the Total Electron Content in order of ±20%, 5%–20% in F‐region plasma drift, and 20%–30% in F‐region neutral winds.

Study of ruthenium film grown in oxygen environment for x-ray optics application

Ru shows high damage threshold as compared to other standard materials Au, Rh and Pt for high heat load applications in high brilliance synchrotron radiation source and x-ray free electron laser. It is also a promising candidate to be used as a protective capping layer in multilayers for increasing their life time. In the present study, Ru thin films of 500Å thickness were deposited in oxygen environment at different substrate temperatures varying from 70°C to 500°C. In reactive ion beam sputtering process, the flow of Ar and reactive O2 gas was maintained in 4:1 ratio keeping total flow 3 SCCM constant. The deposited films were characterized using grazing incidence x-ray reflectivity (GIXRR), grazing incidence x-ray diffraction (GIXRD) and secondary ion mass spectroscopy (SIMS) techniques. A significant change in GIXRR profile was observed in the sample grown at 100°C and 500°C whereas the GIXRD measurements indicated no significant formation of ruthenium oxide at different temperatures. However, a strong peak of Ru2Si3 (222) at 500°C was observed indicating a strong interfacial reaction at ruthenium/ substrate interface.The experimental data suggested a weak signature of RuO2 phase in the films deposited at RT, 70°C and 100°C and therefore the effect of ruthenium oxide with 10% composition in pure ruthenium was calculated on optical performance in extreme ultra violet region of photon energy (85-115 eV).

Evolution Toward 6G Multi-Band Wireless Networks: A Resource Management Perspective

In this article, we first present the vision, key performance indicators, key enabling techniques (KETs), and services of 6G wireless networks. Then, we highlight a series of general resource management (RM) challenges as well as unique RM challenges corresponding to each KET. The unique RM challenges in 6G necessitate the transformation of existing optimization-based solutions to artificial intelligence/machine learning-empowered solutions. In the sequel, we formulate a joint network selection and subchannel allocation problem for 6G multi-band network that provides both further enhanced mobile broadband (FeMBB) and extreme ultra reliable low latency communication (eURLLC) services to the terrestrial and aerial users. Our solution highlights the efficacy of multi-band network and demonstrates the robustness of dueling deep Q-network in obtaining efficient RM solution with faster convergence rate compared to deep Q-network and double deep Q-network algorithms.

Understanding the Exposure Process in the Extreme Ultra Violet Lithography.

Although being the optical lithography, the extreme ultraviolet (EUV) lithography with 13.5-nm wavelength is very different from the deep ultraviolet (DUV) lithography with 193-nm wavelength. Hence, the understanding of the complex detailed EUV mechanisms to cause a chemical reaction in chemically amplified resists (CARs) is required to develop EUV resists and exposure process. In this paper, for organic, metal-organic and metal-oxide resists, the electron-scattering model of exposure mechanisms needs to include the elastic and inelastic mean free paths. On top of that, Dill's parameters of DUV and EUV resisters from the photo-generated reaction are discussed to indicate the physical and chemical characteristics. For CAR and EUV resists, Dill B parameter is large than Dill A and B parameters.

DETEKSI OTOMATIS DAERAH TERANG DI SISI JAUH MATAHARI UNTUK PREDIKSI KEMUNCULAN BINTIK

Active regions that responsible to flare occurrences often appear at east limb as mature active regions. Therefore, we use EUVI instrument onboard STEREO-A spacecraft to observe far-side extreme ultra violet (EUV) for the automatic detection system. The procedure running on the system is by combining the latest STEREO/EUVI and the SDO/AIA data into a single composite heliographic coordinate system map. Active regions are detected based on their intensities on the heliographic map and their duration after they are detected. The program has successfully detected far-side bright-regions in an automatically near real-time system. 85 % of active regions that have been detected for more than 4 days appear in the east limb as sunspots. On the other hand, bright-regions that have detected between 2-3 days develop to be plagues or decay before reaching the east limb. We find that the different between the mean intensities of the bright-regions that develop to sunspot and no-sunspot regions is about 200 DN//s, which is insignificant to determine the threshold.

Automated Detection of Accelerating Solar Eruptions Using Parabolic Hough Transform

Solar eruptions such as Coronal Mass Ejections (CMEs) observed in the inner solar corona (up to 4 R$_{\odot}$) show acceleration profiles which appear as parabolic ridges in height-time plots. Inspired by the white-light automated detection algorithms, Computer Aided CME Tracking System (CACTus) and Solar Eruptive Events Detection System (SEEDS), we employ the parabolic Hough Transform for the first time to automatically detect off-disk solar eruptions {from height-time plots. Due to the limited availability of white-light observations in the inner corona, we use Extreme UltraViolet (EUV) images of the Sun. In this paper we present a new algorithm, CME Identification in Inner Solar Corona (CIISCO), which is based on Fourier motion filtering and the parabolic Hough transform, and demonstrate its implementation using EUV observations taken from {\it Atmospheric Imaging Assembly} (AIA) on-board the Solar Dynamics Observatory (SDO), {\it Extreme Ultra Violet Imager} (EUVI) on-board the STEREO-A and B satellites, and {\it Sun Watcher using Active Pixel System detector and Image Processing} (SWAP) Imager on-board PROBA2. We show that CIISCO is able to identify any {off-disk} outward moving feature in EUV images. The use of automated detection algorithms, like CIISCO, can potentially be used to provide early warnings of CMEs if an EUV telescope is located at $\pm$ 90$^{\circ}$ from the Sun-Earth line, providing CME characteristics and kinematics close to the Sun. This paper also presents the limitations of this algorithm and the prospects for future improvement.

EUV and Hard X-ray Hartmann Wavefront Sensing for Optical Metrology, Alignment and Phase Imaging.

For more than 15 years, Imagine Optic have developed Extreme Ultra Violet (EUV) and X-ray Hartmann wavefront sensors for metrology and imaging applications. These sensors are compatible with a wide range of X-ray sources: from synchrotrons, Free Electron Lasers, laser-driven betatron and plasma-based EUV lasers to High Harmonic Generation. In this paper, we first describe the principle of a Hartmann sensor and give some key parameters to design a high-performance sensor. We also present different applications from metrology (for manual or automatic alignment of optics), to soft X-ray source optimization and X-ray imaging.

Soft x-ray spectroscopies in liquids and at solid-liquid interface at BACH beamline at Elettra.

The beamline for advanced dichroism of the Istituto Officina dei Materiali-Consiglio Nazionale delle Ricerche, operating at the Elettra synchrotron in Trieste (Italy), works in the extreme ultraviolet-soft x-ray photon energy range with selectable light polarization, high energy resolution, brilliance, and time resolution. The beamline offers a multi-technique approach for the investigation of the electronic, chemical, structural, magnetic, and dynamical properties of materials. Recently, one of the three end stations has been dedicated to experiments based on electron transfer processes at the solid/liquid interfaces and during photocatalytic or electrochemical reactions. Suitable cells to perform soft x-ray spectroscopy in the presence of liquids and reagent gases at ambient pressure were developed. Here, we present two types of static cells working in transmission or in fluorescence yield and an electrochemical flow cell that allows us to carry out cyclic voltammetry in situ and electrodeposition on a working electrode and to study chemical reactions under operando conditions. Examples of x-ray absorption spectroscopy measurements performed under ambient conditions and during electrochemical experiments in liquids are presented.

High Sensitivity Resists for EUV Lithography: A Review of Material Design Strategies and Performance Results.

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad consensus on this direction has triggered a dramatic increase of interest on resist materials of high sensitivity especially designed for use in the EUV spectral region in order to meet the strict requirements needed for overcoming the source brightness issues and securing the cost efficiency of the technology. To this direction both fundamental studies on the radiation induced chemistry in this spectral area and a plethora of new ideas targeting at the design of new highly sensitive and top performing resists have been proposed. Besides the traditional areas of acid-catalyzed chemically amplified resists and the resists based on polymer backbone breaking new unconventional ideas have been proposed based on the insertion of metal compounds or compounds of other highly absorbing at EUV atoms in the resist formulations. These last developments are reviewed here. Since the effort targets to a new understanding of electron-induced chemical reactions that dominate the resist performance in this region these last developments may lead to unprecedented changes in lithographic technology but can also strongly affect other scientific areas where electron-induced chemistry plays a critical role.

Understanding Extreme Violent Behavior in Ultra Firms: Exploring Identity Fusion from a Dialogical Perspective

This paper explores a dialogical operationalization of identity fusion in the context of football firms. An in-depth life story interview with a longstanding member of a football firm involved in several violent episodes was qualitatively analyzed. The variety of positions of the self (I-positions) as well as the dialogical relations established by such positions were examined under themes associated with identity fusion, in an attempt to understand pro-group radical violent behavior. Results suggest that a core coalition of internal I-positions and external We-positions favoring extreme ultra violence appeared to dominate the participant’s self-system. This coalition seemed to have soft boundaries among the positions compounding it and, at the same time, rigid boundaries with other positions of the self-system, operating as an I-prison, preventing alternative counter-violence voices to be heard and promoter or meta-positions to emerge. Considering that functionally equivalent forms of identity fusion have been identified in radical football violence and terrorism, this knowledge can contribute to tackle the pathways for engaging in extreme violence in favor of a group/organization. Moreover, it can be used to develop more effective programs to promote individuals’ de-fusion from different groups, whenever group adherence proves dysfunctional and risky for themselves and/or others.

Local profiles of line emission of impurity ions in rotating fusion plasmas

We analyze the poloidal distribution of impurity ions, such as C V, C VI and O VIII, in fast rotating KSTAR plasmas using the impurity emission lines in the 1–7 nm wavelength range obtained from the space-resolved extreme ultra violet spectrometer. This is aided particularly by a new tomographic reconstruction technique with limited viewing angles. The vacuum and extreme ultraviolet spectrometer system at ITER and its prototypes installed at KSTAR are one of the main diagnostic systems to monitor the impurity species in fusion plasmas; however, they have an insufficient field of view to utilize the conventional reconstruction method. The new algorithm developed in this work considers a curvilinear grid of pixels mapped onto the magnetic equilibrium and a weight factor considering toroidal rotational effect on impurity species. Validation tests with poloidally asymmetric images of synthetic plasma demonstrate that this method is highly useful for emission diagnostics that have a narrow field of view. The experimental results of the spatially resolved spectra from KSTAR plasma clearly show that even the light impurities such as carbon and oxygen are significantly affected by the toroidal rotation. Accordingly, the method is expected to be utilized for estimating the poloidal density profile of each charge state of an impurity species, which will play a key role in impurity transport studies.

High-precision Dark Halo Virial Masses from Globular Cluster Numbers: Implications for Globular Cluster Formation and Galaxy Assembly

Abstract We confirm that the number of globular clusters (GCs), N GC, is an excellent tracer of their host galaxy’s halo virial mass, M vir. The simple linear relation M vir = 5 × 109 M ⊙ × N GC fits the data perfectly from M vir = 1010 M ⊙ to M vir = 2 × 1015 M ⊙. This result is independent of galaxy morphology and extends statistically into the dwarf galaxy regime with M vir = 108–1010 M ⊙, including the extreme ultra diffuse galaxy DF44. As this correlation does not depend on GC mass, it is ideally suited for high-precision determinations of M vir. The linearity is most simply explained by cosmological merging of a high-redshift halo seed population that hosted on average one GC per 5 × 108 M ⊙ of dark matter. We show that hierarchical merging is also extremely powerful in restoring a linear correlation and erasing signatures of even a strong secular evolution of GC systems. The cosmological merging scenario also implies a strong decline of the scatter in N GC with increasing virial mass in contrast with the observations that show a roughly constant scatter, independent of virial mass. This discrepancy can be explained if errors in determining virial masses from kinematical tracers and gravitational lensing are on the order of a factor of 2. GCs in dwarf satellite galaxies pose a serious problem for high-redshift GC formation scenarios; the dark halo masses of dwarf galaxies hosting GCs therefore might need to be an order of magnitude larger than currently estimated.

MULTI-WAVELENGTH OBSERVATIONS OF A LARGE SOLAR FLARE

We present the results of the multi- wavelength study of the two-ribbon solar flare on July 19, 2000 in the active region NOAA 9087. The evo- lution and morphological properties of the flare pro- ductive active region have been analyzed. The active region was growing rapidly and showed a complex mul- tipolar magnetic field configuration. It was large, pro- ducing many events, including the flare under consid- eration. The 3N/M6.4 two-ribbon flare was a promi- nent, long duration event in the active region evolution. According to Solar Geophysical Data (SGD) the flare lasted 2.5 hours. The flare energy release took place in many sites of the active region. We used combination of data from space and ground based observatories for study. The hard X-ray (HXR) and soft X-ray (SXR) data were obtained at the Yohkoh Telescopes (HXT and SXT) and Geostationary Operational Environmental Satellite (GOES). The full- disk magnetograms and EUV-images were provided by the Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI) and Extreme ultra- violet Imaging Telescope (EIT). We used the H α filter- grams from the Meudon spectroheliograph and white light images of Big Bear Solar Observatory (BBSO). All the data show continuously evolving SXR, EUV and H α features during the flare. The HXR and the type III radio bursts were observed at the flare onset. The first H α flare kernels and the surge, connected with the filament eruption, were initiated near a large positive-polarity sunspot. The main bright kernels of the flare occurred at the centre of the active region near magnetic neutral line, after that the flare ribbons appeared along it. It was found that HXR coronal source was located along a magnetic polarity inversion line of the active region. EUV loop structures indicate the observational evidence of a magnetic reconnection during the main phase of the flare.

The FitCoPI Code: Iterative Determination of the 3D Density and Temperature Configuration in the Active-Region Corona

For understanding the physical processes in the solar corona, it is helpful to reconstruct the 3D-distribution of plasma density and temperature. We introduce a new iterative method that uses multi-filter observations and an extrapolated coronal magnetic field to fit the physical parameters along the field lines to the observations. Since a model is applied only for the field extrapolation but not to the loops themselves, non-stationary plasma configurations along the loops can be captured. We demonstrate the performance of our code on a self-made model active-region corona and on active region (AR) 11087 observed by the Solar Dynamics Observatory and the Solar Terrestrial Relation Observatory-A in 2010. In the coronal parts of the model AR, the 25% quantile of the deviations of the reconstructed densities relative to the model values is −0.5 to −0.6 below the model values, the 75% quantile being 0.3. Likewise, for the logarithm of the temperature, the same quantiles are at minus and plus 0.04, respectively, relative to the model values. For AR 11087, the seven channels of the Atmospheric Imaging Assembly in the extreme ultraviolet are reproduced very well. For the four channels of the Extreme Ultra Violet Imager in that regime, the synthesised images are slightly brighter than the observations. The structure of the AR can still be identified here.

Solar flares and the axion quark nugget dark matter model

Abstract We advocate the idea that the nanoflares conjectured by Parker long ago to resolve the corona heating problem, may also trigger the larger solar flares. The arguments are based on the model where emission of extreme ultra violet (EUV) radiation and soft X-rays from the Sun are powered externally by incident dark matter particles within the Axion Quark Nugget (AQN) Dark Matter Model. The corresponding annihilation events of the AQNs with the solar material are identified with nanoflares. This model was originally invented as a natural explanation of the observed ratio Ω dark ∼ Ω visible when the DM and visible matter densities assume the same order of magnitude values. This model gives a very reasonable intensity of EUV radiation without adjustments of any parameters in the model. When the same nuggets enter the regions with high magnetic field they serve as the triggers igniting the magnetic reconnections which eventually may lead to much larger flares. Technically, the magnetic reconnection is ignited due to the shock wave which inevitably develops when the dark matter nuggets enter the solar atmosphere with velocity v AQN ∼ 600 km∕s which is much higher than the speed of sound c s , such that the Mach number M = v AQN ∕ c s ≫ 1 . These shock waves generate very strong and very short impulses expressed in terms of pressure Δ p ∕ p ∼ M 2 and temperature Δ T ∕ T ∼ M 2 in vicinity of (would be) magnetic reconnection area. We find that this mechanism is consistent with X-ray observations as well as with observed jet like morphology of the initial stage of the flares. The mechanism is also consistent with the observed scaling of the flare distribution d N ∼ W − α d W as a function of the flare’s energy W . We also speculate that the same nuggets may trigger the sunquakes which are known to be correlated with large flares.

Mask Materials and Designs for Extreme Ultra Violet Lithography

Extreme ultra violet lithography (EUVL) is no longer a future technology but is going to be inserted into mass production of semiconductor devices of 7 nm technology node in 2018. EUVL is an extension of optical lithography using extremely short wavelength (13.5 nm). This short wavelength requires major modifications in the optical systems due to the very strong absorption of EUV light by materials. Refractive optics can no longer be used, and reflective optics is the only solution to transfer image from mask to wafer. This is why we need the multilayer (ML) mirror-based mask as well as an oblique incident angle of light. This paper discusses the principal theory on the EUV mask design and its component materials including ML reflector and EUV absorber. Mask shadowing effect (or mask 3D effect) is explained and its technical solutions like phase shift mask is reviewed. Even though not all the technical issues on EUV mask are handled in this review paper, you will be able to understand the principles determining the performance of EUV masks.

Compensation of high order harmonic long quantum-path attosecond chirp

We propose a method to compensate for the extreme ultra violet (XUV) attosecond chirp associated with the long quantum-path in the high harmonic generation process. Our method employs an isolated attosecond pulse (IAP) issued from the short trajectory contribution in a primary target to assist the infrared driving field to produce high harmonics from the long trajectory in a secondary target. In our simulations based on the resolution of the time-dependent Schrödinger equation, the resulting high harmornics present a clear phase compensation of the long quantum-path contribution, near to Fourier transform limited attosecond XUV pulse. Employing time–frequency analysis of the high harmonic dipole, we found that the compensation is not a simple far-field photonic interference between the IAP and the long-path harmonic emission, but a coherent phase transfer from the weak IAP to the long quantum-path electronic wavepacket. Our approach opens the route to utilizing the long quantum-path for the production and applications of attosecond pulses.