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 Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Seeing the quantum future... literally
16.01.2017 | University of Sydney

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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>