EPJ D Colloquium: Non-equilibrium in low-temperature plasmas

The wide range of applications that have been found for cold plasmas stems from the fact that they are physical systems out of thermodynamic equilibrium. This property enhances their reactivity at low gas temperature, and allows macroscopic effects to be obtained with only moderate energy consumption.

In this EPJ D review, the basic concepts of ionised gases in a non-equilibrium state are treated by showing how and why the non-equilibrium functions of the degrees of freedom are formed in a variety of natural and man-made plasmas, with particular emphasis on the progress that has been made in the last decade. A modern perspective of the molecular basis of non-equilibrium and of a state-to-state kinetic approach is adopted. Computational and diagnostic techniques that have been used to investigate the non-equilibrium conditions are also surveyed.

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EPJ D Highlight - Better than milk on breakfast cereals: new precision coating method for industrial granular material

Ignited plasma – starfish shaped racetracks.

Deposition of a thin film catalyst of a predicted thickness on the surface of novel hydrogen storage microbeads helps release hydrogen

As anyone who eats their cereal with milk in the morning knows: coating large volumes of granular material homogeneously is no mean feat. In a recent paper published in EPJ D, an Austrian team has developed a new method, based on physical vapour deposition, to upscale the quantity of coating without affecting the quality and homogeneity of the film. In this study, Andreas Eder from Vienna University of Technology and colleagues also developed a model capable of predicting the film thickness. This represents a major step forward for industrial materials, as previous approaches relied on optical measurement after the coating had been deposited. Because this coating system is capable of implementing a plasma close to the granular substrate, it opens the door to new surface treatment and modification possibilities.

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EPJ D Colloquium: Evaluating experimental molecular physics studies of radiation damage in DNA

Molecular physics has made significant new contributions to our understanding of radiation damage at the molecular level, and led to improved cancer therapy through both experimental and theoretical advances, in particular the development of new damage measurement and analysis techniques.

In this EPJ D Colloquium paper, Małgorzata A. Śmiałek summarizes and highlights the most prominent findings in atomic and molecular physics, that have contributed towards a better understanding of the fundamental processes in biological systems and relevant to the next generation of radiation therapies. She also comments on the practical experimental challenges that have been met while investigating the more complex targets.

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EPJ D Highlight - When quantum scale affects the way atoms emit and absorb particles of light

The meanfield phase diagrams of the Jaynes-Cummings-Hubbard (left) and Rabi-Hubbard (right) models.

Exact simulation lifts the 80-year-old mystery of the degree to which atoms can be dressed with photons

In 1937, US physicist Isidor Rabi introduced a simple model to describe how atoms emit and absorb particles of light. Until now, this model had still not been completely explained. In a recent paper, physicists have for the first time used an exact numerical technique: the quantum Monte Carlo technique, which was designed to explain the photon absorption and emission phenomenon. These findings were recently published in EPJ D by Dr Flottat from the Nice –Sophia Antipolis Non Linear Institute (INLN) in France and colleagues. They confirm previous results obtained with approximate simulation methods.

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EPJ D Highlight - Inside an ion-molecule collision

An author’s conception of the collision of incoming positively charged ion beam into a furan molecule.

Physicists elucidate reactions underlying positive ion beams hitting molecular targets relevant in proton therapy

Ion-molecule reactions are ubiquitous. They are important in the emergence of primordial life as solar wind falls onto chemicals turning them into the prebiotic building blocks of life. Ion-molecule reactions are also the basic process underlying the proton-biomolecule collisions relevant in proton therapies in cancer. To better understand these mechanisms, a new study provides novel data on low-energy proton collisions with furan and its derivative molecules, which are models for the deoxyribose sugar unit found in biological processes. These findings have been published in EPJ D by Tomasz Wasowicz from Gdansk University of Technology, Poland, and colleagues, as part of the topical issue “Low-Energy Interactions related to Atmospheric and Extreme Conditions.”

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Plasma Physicist Kurt H. Becker Elected to Board of Directors of National Academy of Inventors

Kurt Becker
Kurt Becker Ph.D - former Editor-in-Chief of EPJ D and currently serving as the North American Regional Editor for the journal as well as an Editor for EPJ Special Topics - vice dean for research, innovation and entrepreneurship at NYU Tandon School of Engineering has been named to the board of directors of the National Academy of Inventors. For more information, see the press release on http://engineering.nyu.edu

EPJ D Highlight - Electron scavenging to mimic radiation damage

Molecule of trifluoroacetamide (TFAA).

New study could help unveil negative effect of radiation on biological tissues due to better understanding of low energy electron-induced reactions

High energy radiation affects biological tissues, leading to short-term reactions. These generate, as a secondary product, electrons with low energy, referred to as LEEs, which are ultimately involved in radiation damage. In a new study, scientists study the effect of LEEs on a material called trifluoroacetamide (TFAA). This material was selected because it is suitable for electron scavenging using a process known as dissociative electron attachment (DEA). These findings were recently published in EPJ D by Janina Kopyra of Siedlce University, Poland, and colleagues in Germany, as part of a topical issue on Advances in Positron and Electron Scattering.

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EPJ D Highlight - Better material insights with gentle e-beams

An early 2-D EELS of nitrogen.

Great potential for a new, more accurate, tool for using electron collisions to probe matter

There are several ways to change a molecule, chemically or physically. One way is to heat it; another is to bombard it with light particles, or photons. A lesser known method relies on electron collision, or e-beam technology, which is becoming increasingly popular in industry. In a review outlining new research avenues based on electron scattering, Michael Allan from the University of Fribourg, Switzerland and colleagues explain the subtle intricacies of the extremely brief electron-molecule encounter, in particular with gentle, i.e., very low energy electrons. In this paper, which was recently published in EPJ D, the authors describe how the use of very low energy electrons and a number of other performance criteria, make the approach with the so-called Fribourg instrument a more appealing candidate than previously available tools used to study electron collisions.

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EPJ D Highlight - Revisiting trajectories at the quantum scale

The laws of physics governing the macro scale appear to be an approximation of what is happening at the quantum scale. © hywards / Fotolia

The role of statistics in quantum scale observation explains microscale behaviour

There is a gap in the theory explaining what is happening at the macroscopic scale, in the realm of our everyday lives, and at the quantum level, at microscopic scale. In this paper published in EPJ D, Holger Hofmann from the Graduate School of Advanced Sciences of Matter at Hiroshima University, Japan, reveals that the assumption that quantum particles move because they follow a precise trajectory over time has to be called into question. Instead, he claims that the notion of trajectory is a dogmatic bias inherited from our interpretation of everyday experience at the macroscopic scale. The paper shows that trajectories only emerge at the macroscopic limit, as we can neglect the complex statistics of quantum correlations in cases of low precision.

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EPJ D Highlight - How repeated spot microdischarges damage microdevices

Simulated velocity field of the microfilament in the vicinity of the dielectric wall after the train of 150 localised breakdowns

New study blames temperature increase on locally reoccurring discharges in microelectronic devices

In microelectronics, devices made up of two electrodes separated by an insulating barrier are subject to multiple of microdischarges—referred to as microfilaments—at the same spot. These stem from residual excited atoms and ions from within the material, the surface charge deposited on the insulating part of the device, and local temperature build-up. These reoccurences can lead to the creation of pin-holes in the material of the microelectronic devices where they occur, and are due to local reductions in the electric field. Now, Jozef Ráhel and colleagues from Masaryk University in the Czech Republic have elucidated the mechanism of microdischarge reoccurrence, by attributing it to the temperature increase in a single microdischarge. These results were recently published in EPJ D.

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