Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A matter-antimatter plasma

04.05.2015

In everyday life matter takes on three different forms or states: solid, liquid, and gas. In addition, dueto its unique properties, a plasma, i.e. an overall almost neutral, ionized gas consisting of positive ions and free electrons, is also customarily considered as the fourth state of matter.

Now, an experimental group from the Queen's University of Belfast in strong collaboration with the Quantum Dynamics Theory Division of the Max Planck Institute for Nuclear Physics has generated a novel form of plasma, exclusively made of electrons and their antimatter counterpart (positrons) in the laboratory [Nature Communications 23.04.2015].

Now, an experimental group from the Queen's University of Belfast in strong collaboration with the Quantum Dynamics Theory Division of the Max Planck Institute for Nuclear Physics has generated a novel form of plasma, exclusively made of electrons and their antimatter counterpart (positrons) in the laboratory [Nature Communications 23.04.2015].


Fig. 1: Experiment vs. theory for electron (a) and positron (b) yield and positron percentage (c). Blue: exp data; red: FLUKA simulation; green: analytical model, scaled by 0.75 in (a) and (b).

Queen's University Belfast / MPIK

The positron is the antiparticle of the electron which shares with the latter all properties except the charge having opposite sign. Electron-positron plasmas are emitted as ultra-relativistic jets in different astrophysical scenarios under extreme conditions, like during gamma-ray bursts.

Thus, they represent a unique tool to test physics in so far unexplored regimes also providing deeper insights about the early stages of the Universe. The feasibility of generating such a unique state of matter in a terrestrial laboratory would then open the possibility of scrutinizing such phenomena and regimes under controlled conditions.

This goal has been now achieved by an experimental team led by Dr. Gianluca Sarri and Prof. Matthew Zepf from the Queen's University of Belfast in strong collaboration with Antonino Di Piazza and Christoph H. Keitel from the Division for Theoretical Quantum Dynamics of the Max Planck Institute for Nuclear Physics in Heidelberg.

The experiment has been performed at the Astra Gemini laser facility at the Rutherford Appleton Laboratory, Oxford, United Kingdom. An ultra-relativistic electron beam, generated in an all-optical setup via laser wake-field acceleration, hit a Pb solid target. As a consequence of the complex interaction of the electron beam with the nuclei and the electrons in the target, an ultra-relativistic electron-positron bunch was observed on the rear side of the solid target, with a fraction of electrons and positrons depending on the target thickness (see Fig. 1).

The density of the bunch was found to be sufficiently high that its skin-depth resulted smaller than the bunch transverse size, allowing for collective, i.e., plasma effects. "Our main task", says Antonino Di Piazza, the first theory author of the publication, "was to identify the main mechanism responsible of the production of the electron-positron bunch and to describe its formation and evolution inside the solid target in the most concise and simple way, in order to shed light on the underlying physics".

The result is a surprisingly simple model, which, among all possible interactions occurring inside the solid target, includes only two fundamental quantum electrodynamical processes: 1) bremsstrahlung by electrons and positrons, and 2) electron-positron pair production by photons, both occurring in the presence of the screened electromagnetic field of the solid target atomic nuclei. Analytical estimations and numerical integrations of the corresponding kinetic equations agree very well with the experimental results on the relative population of electrons and positrons in the generated beam (see in particular the blue dots and the green dashed line in part c of the Fig. 1).

Absolute electron and positron yields were also well predicted by the model. In order to reproduce theoretically also more detailed features of the experimental results, Gianluca Sarri has employed the available fully integrated particle physics Monte-Carlo simulation code FLUKA (red dots in Fig. 1), which among others also includes the electron-electron and electron-positron interactions, atomic scattering and other breaking mechanisms together with high-energy processes like production of muon-antimuon pairs (the next heavier relatives of electrons/positrons among the elementary particles). Those mechanisms reduce the yield compared to the analytical model by about 25%.

Original paper:

Generation of neutral and high-density electron–positron pair plasmas in the laboratory
G. Sarri, K. Poder, J. Cole, W. Schumaker, A. Di Piazza, B. Reville, T. Dzelzainis, D. Doria, L.A. Gizzi, G. Grittani, S. Kar, C.H. Keitel, K. Krushelnick, S. Kuschel, S.P.D. Mangles, Z. Najmudin, N. Shukla, L.O. Silva, D. Symes, A.G.R. Thomas, M. Vargas, J. Vieira and M. Zepf
Nature Communications 6:6747 (2015); DOI: 10.1038/ncomms7747

Contact:

PD Dr. Antonino Di Piazza
MPI for Nuclear Physics
Phone.: +49 6221 516-161
E-mail: dipiazza@mpi-hd.mpg.de

Dr. Gianluca Sarri
Centre for Plasma Physics
Queen’s University Belfast
Phone: +44 28 9097 3575
E-mail: g.sarri@qub.ac.uk

Weitere Informationen:

http://www.nature.com/ncomms/2015/150423/ncomms7747/full/ncomms7747.html Original paper
http://www.mpi-hd.mpg.de/keitel/dipiazza Group High-Energy Quantum Electrodynamics, MPIK
http://www.qub.ac.uk/research-centres/CentreforPlasmaPhysics Centre for Plasma Physics, Queen's University Belfast
https://www.stfc.ac.uk/CLF/Facilities/Astra/Astra+Gemini/12258.aspx Laser system Gemini, Rutherford Appleton Laboratory

Dr. Bernold Feuerstein | Max-Planck-Institut für Kernphysik

More articles from Physics and Astronomy:

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology

nachricht Light rays from a supernova bent by the curvature of space-time around a galaxy
21.04.2017 | Stockholm University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Molecular libraries for organic light-emitting diodes

24.04.2017 | Life Sciences

Research sheds new light on forces that threaten sensitive coastlines

24.04.2017 | Earth Sciences

Making lightweight construction suitable for series production

24.04.2017 | Machine Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>