2022 Impact factor 3.4

EPJ D Highlight - Machine learning hunts for the right mix of hydrogen isotopes for future nuclear fusion power plants

The Sun, where nuclear fusion of hydrogen proceeds in a dense plasma. New research uses machine learning to look for the right mix of hydrogen isotopes for technology that replicates this process on Earth. Credit: ESA/NASA/SOHO

New research is an initial step in the use of deep learning to help determine the right mix of hydrogen isotopes to use in fusion power plants of the future

The process that powers the stars, nuclear fusion, is proposed as a future power source for humanity and could provide clean and renewable energy free of the radioactive waste associated with current nuclear fission plants.

Just like the fusion process that sends energy spilling out from the Sun, future nuclear fusion facilities will slam together isotopes of the universe’s lightest element, hydrogen, in an ultra-hot gas or “plasma” contained by a powerful magnetic field to create helium with the difference in mass harvested as energy.

One thing that scientists must know before the true advent of fusion power here on Earth is what mix of hydrogen isotopes  to use— primarily “standard” hydrogen, with one proton in its atomic nucleus, deuterium with one proton and one neutron in its nucleus, and tritium with a nucleus of one proton and two neutrons. This is currently done with spectroscopy for prototype fusion devices called tokamaks, but this analysis can be time-consuming.

In a new paper in EPJ D, author Mohammed Koubiti, Associate Professor at the Aix-Marseille Universite, France, assesses the use of machine learning in connection with plasma spectroscopy to determine the ratios of hydrogen isotopes for nuclear fusion plasma performance.

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EPJ D Topical Issue: Electron-Driven Processes from Single Collisions to High-Pressure Plasmas

Guest Editors: Jose L. Lopez, Michael Brunger, and Holger Kersten

The special Topical Issue of the European Physics Journal D (EPJ D) on “Electron-Driven Processes from Single Collisions to High-Pressure Plasmas” is published to honor Kurt H. Becker, who served as Editor-in-Chief for the journal from 2010 to 2016, on his 70th birthday. Electron-driven processes from single collisions to high-pressure plasmas definitely occupy a central position in atomic and plasma physics. Considering this, the Guest Editors compilated a broad range of original manuscripts that encompass the area of electron-atom and electron-molecular collisions, respectively, low-temperature plasma research and aligning with Kurt Becker’s emphasis on science innovation and entrepreneurship. Hence, the papers focus on various recent scientific and technological advances in this given area of physics, chemistry and technology of non-thermal plasmas.

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EPJ D Highlight - Looking deeper into graphene using rainbow scattering

An illustration of a kilonova the collision of neutron stars generating conditions extreme enough to forge the Universe’s heavy elements. Credit: Robin Dienel/The Carnegie Institution for ScienceContact

New research uses protons to shine a light on the structure and imperfections of this two-dimensional wonder material

Graphene is a two-dimensional wonder material that has been suggested for a wide range of applications in energy, technology, construction, and more since it was first isolated from graphite in 2004.

This single layer of carbon atoms is tough yet flexible, light but with high resistance, with graphene calculated to be 200 times more resistant than steel and five times lighter than aluminium.

Graphene may sound perfect, but it very literally is not. Isolated samples of this 2D allotrope aren’t perfectly flat, with its surface rippled. Graphene can also feature structural defects that can, in some cases, be deleterious to its function and, in other instances, can be essential to its chosen application. That means that the controlled implementation of defects could enable fine-tuning of the desired properties of two-dimensional crystals of graphene.

In a new paper in EPJ D, Milivoje Hadžijojić and Marko Ćosić, both of the Vinča Institute of Nuclear Sciences, University of Belgrade, Serbia, examine the rainbow scattering of photons passing through graphene and how it reveals the structure and imperfections of this wonder material.

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EPJ D Highlight - Looking deeper into violent neutron star collisions to find the origins of heavy elements

An illustration of a kilonova the collision of neutron stars generating conditions extreme enough to forge the Universe’s heavy elements. Credit: Robin Dienel/The Carnegie Institution for ScienceContact

The gold that makes up your most precious jewellery may have been forged in a violent cosmic collision millions or billions of light years away between two neutron stars. New research seeks to better understand this process.

There is only a single confirmed site in the Universe capable of generating conditions extreme enough to initiate the production process for many of the heaviest elements in the Universe, including gold, platinum, uranium – neutron star mergers. These mergers are the only event observed to-date that can produce the incredible densities and temperatures needed to power the rapid neutron capture process.

In a new paper in EPJ D, Andrey Bondarev, a postdoc researcher at Helmholtz Institute Jena, James Gillanders a postdoc researcher in Rome, and their colleagues examine the spectra from the kilonova AT2017gfo to investigate the presence of forged tin, by looking for spectral features caused by its forbidden transitions.

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EPJ D Topical Issue: Precision Physics of Simple Atomic Systems

Guest Editors: Krzysztof Pachucki, Thomas Udem, Wim Ubachs, Paolo Crivelli & Stefan Ulmer

This EPJD special issue dedicated to the field of precision physics of simple atomic systems includes several important peer-reviewed contributions, presented on the 11th edition of the PSAS conference —initially planned to take place in May 2020 in Wuhan, China (only to be rescheduled 2 years later, in May 2022, due to the COVID-19 pandemic, in Warsaw, Poland).

The aim of the PSAS conference is to gather scientists from all over the world working on precise calculations and measurements, with the goal to test fundamental physics, to verify laws of physics, and to determine fundamental constants. Correspondingly, a mix of theoretical, numerical and experimental works spanning the fields of spectroscopy of atomic and molecular hydrogen, QED of few-electron bound systems, exotic atoms and ions, searches for BSM physics with atoms and antimatter, clocks, measurements of g-2 and alpha, originating from several of the major groups in this field, are reported here, making the current collection of interest for both the younger generation entering this research field and experts for efficient access on recent developments.

All articles are available here and are freely accessible until 29 August 2023. For further information read the Editorial.

EPJ D Highlight - Testing a perfect absorber metamaterial

The schematic picture of a proposed perfect absorber metamaterial

The proposed metamaterial could have a wide range of applications, from sensing to stealth technology

Metamaterials are a type of artificial material which, as the prefix “meta” – meaning in Greek “after” or “beyond” – indicates, demonstrate electromagnetic properties and other characteristics not found in nature.

As a result of these characteristics, including negative refraction and perfect lensing and cloaking, which arise from the lattice design composition of these substances rather than the materials that actually comprise them, metamaterials have become a hot research topic.

In particular, materials scientists are actively hunting for metamaterials that are “perfect absorbers” of electromagnetic radiation with controllable resonance characteristics that lead to their wide usage in applications as varied as solar cells, thermal radiation imaging, sensing technology, and even stealth technology.

In a new paper in EPJ D, Shahzad Anwar, a researcher at the Department of Physics, Islamia College Peshawar, Pakistan, and his colleagues document the proposed design of a triple-band perfect metamaterial absorber. The new metamaterial could have applications in sensors, filters, and in stealth technology.

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EPJ D Highlight - A broader approach to quantum walks

Simulating an evolving quantum system

Quantum walks have been widely studied for their ability to simulate real physical phenomena. Physicists previously studied two distinct types of quantum walk, but so far, they haven’t widely considered how their mathematical descriptions could be linked. Through new research published in EPJ D, a pair of physicists in France: Nicolas Jolly at ENS de Lyon, and Giuseppe Di Molfetta at Aix-Marseille University, show how ‘discrete-‘ and ‘continuous-time’ quantum walks can be described using more general mathematical language. Their results could allow researchers to simulate an even broader range of phenomena using quantum walks.

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EPJ D Topical Issue: Dynamics of Systems on the Nanoscale (2021)

Guest Editors: Alexey V. Verkhovtsev, Vincenzo Guidi, Nigel J. Mason, Andrey V. Solov’yov

Understanding the Dynamics of Systems on the Nanoscale forms the core of a multidisciplinary research area addressing many challenging interdisciplinary problems at the interface of physics, chemistry, biology, and materials science. They include problems of structure formation, fusion and fission, collision and fragmentation, surfaces and interfaces, collective electronic excitations, reactivity, nanoscale phase and morphological transitions, irradiation driven transformations of complex molecular systems, biodamage, channeling phenomena, and many more. Common to these interdisciplinary scientific problems is the central role of the structure formation and dynamics of animate and inanimate matter on the nanometer scale.

This topical issue presents a collection of research papers devoted to different aspects of the Dynamics of Systems on the Nanoscale, ranging from fundamental research on elementary atomic and molecular mechanisms to studies at a more applied level, covering innovative theoretical, experimental and computational modeling techniques. Some of the contributions discuss specific applications of the research results in several modern and emerging technologies, such as controlled nanofabrication with charged particle beams or the design and practical realization of novel gamma-ray crystal-based light sources.

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EPJ D Highlight - Better understanding the bonds between carbon group elements

Experimental setup

Heating clusters of these elements reveals key differences

The bonds between clusters of elements in the fourteenth group of the periodic table are known to be fickle. Ranging from the nonmetal carbon, to the metalloids silicon and germanium, to the metals tin and lead, all these elements share the same configuration of valence electrons – electrons in their atoms’ outermost energy level. However, clusters formed from these elements respond differently to being excited with laser pulses. Studying the response of atomic clusters to photoexcitation as a function of the element they are composed of and their number of atoms reveals patterns that can be used to gain insight into their structure and binding mechanisms.

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EPJ D Highlight - Predicting the composition of a steel alloy

Experimental setup

Austenitic steel is a potential material for nuclear fusion reactors

Producing energy on Earth through nuclear fusion, the type of reaction that powers the Sun, has proven to be a major challenge. The extreme conditions needed for such a reaction require the walls of a nuclear fusion device to be made of a material with a particular set of mechanical properties, including being able to withstand incredibly high temperatures and be shock- and corrosion-resistant. Austenitic steel, a non-magnetic steel with a crystalline structure, is one of the materials considered for use in nuclear fusion devices.

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Editors-in-Chief
B. Fraboni and G. García López
Thank you very much for your assistance and quick and excellent handling of the manuscript.

Jakub Bielecki, Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland

ISSN: 2190-5444 (Electronic Edition)

© Società Italiana di Fisica and
Springer-Verlag