Proceedings

EPJ D Highlight - Electron-impact ionization calculations match with experiments

Visualising electron-impact ionization cross-sections

Through a new calculation approach, researchers have made far more accurate predictions of how atoms are ionized when impacted by high-energy electrons.

During electron-impact ionization (EII), high-energy electrons collide with atoms, knocking away one or more of their outer electrons. To calculate the probability that ionization will occur during these impacts, researchers use a quantity named the ionization ‘cross-section’. EII is among the main processes affecting the balance of charges in hot plasma, but so far, its cross-section has proven incredibly difficult to study through theoretical calculations.

Through new research published in EPJ D, Stefan Schippers and colleagues at Justus-Liebig University of Giessen, Germany, present new calculations for the EII cross-section, which closely match with their experimental results. Their discoveries could provide useful new insights in many fields of research where hot plasma is studied: including astrophysics and controlled nuclear fusion.

So far, EII cross-sections have proven especially challenging to calculate for two key reasons: the complex interactions which can emerge between the electrons involved in the process, and the wide array of possible electron configurations in the atoms being impacted.

In their study, Schippers’ team tackled these challenges by accounting for several important aspects of the EII process in their calculations: including the relativistic properties of fast-moving electrons, and quantum-scale interactions between electrons and ions. Rather than focusing on the individual electron configurations of the atoms being impacted, they also considered the average effect of many different electronic configurations.

The researchers tested their approach by calculating both the single- and double-EII cross-sections of multiply charged xenon ions, across a broad range of collision energies. They then compared these theoretical values with real experimental results. In most cases, their theoretical cross-sections agreed closely with their experiments – only becoming less accurate at lower collision energies, on the threshold of where ionization can occur. Based on this success, Schippers and colleagues now hope their approach could offer important guidance for EII cross-section calculations in future studies.

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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