Collimated and neutral electron-positron plasmas in the laboratory

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Mathematics and Physics

Abstract

An electron-positron pair plasma (EPP) is a unique state of matter that presents an exact symmetry between its negatively charged (electrons) and positively charged (positrons) constituents. Despite being virtually absent on Earth, it is believed to be a rather common occurrence in the Universe and it is thought to represent the main constituent of the atmosphere of immense astrophysical objects such as black holes, quasars, and pulsars. There is general consensus in the astrophysical community that EPPs are likely candidates for being the main ingredient of some of the most powerful emissions of matter from these objects, in the form of collimated jets, which are ultimately associated with the emission of ultra-bright and short-lived gamma-ray bursts. These astrophysical objects are exceptional natural laboratories to test physics at its limits and, due to their immense distance from Earth (some exceeding a billion light years), they provide a unique window on the primordial stages of our Universe.

Despite their fascinating role in a wide range of fundamental physical scenarios, EPPs are poorly understood due to the extreme difficulty in generating them in the laboratory. All our knowledge of this peculiar state of matter relies exclusively on astrophysical observations and their theoretical interpretation. However, astrophysical measurements are intrinsically limited and it is virtually impossible to access the microphysics of these objects due to their immense distance from Earth. Laboratory experiments would greatly advance our knowledge of this state of matter and only recently the Principal Investigator and his collaborators have succeeded in producing a neutral electron-positron plasma in the laboratory.

We propose here to continue this line of exciting experimental research by performing a series of experiments using the HERCULES laser hosted by the Centre for Ultrafast Optical Sciences (CUOS) at the University of Michigan, US. In particular, we plan to improve the quality of laser-generated EPPs by minimising their divergence and therefore significantly extend their propagation distance in controlled background electron-ion plasmas. The successful generation of a collimated and neutral EPP will allow, for the first time, for the study of EPP dynamics in background electron-ion plasmas in conditions of relevance to the propagation of astrophysical jets in the intergalactic medium. This preliminary work will not only be of interest in its own right but it will also serve as the basis for obtaining more extended grant funding on this newly developing area of experimental research.

Planned Impact

The results of the proposed research will be greatly beneficial for the plasma physics community as well as the astrophysical community. In both cases, it is envisaged that the generation of collimated and neutral electron-positron beams will attract great interest from both the more experimentally and theoretically minded academics. For the former, it would represent a precious tool for the detailed study of pair plasmas in the laboratory, whereas for the latter it would represent an unmatched opportunity for benchmarking numerical calculations and validating theoretical models routinely used in the interpretation of astrophysical observations.

When successful, the proposed research will pave the way for a new branch of experimental physics, namely the laboratory study of electron-positron plasmas and the laboratory small-scale reproduction of astrophysical jets.

Moreover, we envisage that the achievement of the proposal's objectives is likely to fascinate the layman as well. Great interest has already been generated around the preliminary results obtained by the Principal Investigator and his collaborators, as demonstrated by dedicated media coverage in popular science magazines (such as the New Scientist) and websites (such as Physics World, The Conversation UK, and IFL Science). A dedicated article on the work of the Principal Investigator in this area has already been read by more than 120,000 people, placing it to be the 6th most read article in The Conversation of all times. The generation of a small-scale astrophysical jet in the laboratory is likely to attract similar popular interest, boosting the perception of science in the UK.

Publications

10 25 50
 
Description Even though at the start of the grant, we have already made significant progress and already produced high-quality experimental and theoretical results that are published in high-profile scientific journals. Ongoing collaborations/experiments stemming from these results
Exploitation Route Academic impact, progress in understanding of physics
Sectors Environment,Other

 
Description collaboration with Rolls Royce ongoing in order to produce advanced systems for material testing
Sector Aerospace, Defence and Marine
Impact Types Economic

 
Description EPSRC platform grant
Amount £1,389,644 (GBP)
Funding ID EP/P010059/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2017 
End 12/2020
 
Description Experimental work: HERCULES 
Organisation Australian National University (ANU)
Department Department of Nuclear Physics
Country Australia 
Sector Academic/University 
PI Contribution collaborative experiments
Collaborator Contribution collaborative experiments including the use of their laser laboratory: HERCULES
Impact publication of high profile articles in world-leading journals.
Start Year 2011
 
Description ICL collaboration 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution collaborative experiments
Collaborator Contribution collaborative experiments
Impact publication of high profile articles in world-leading journals
Start Year 2011
 
Description QED experiments 
Organisation University of Michigan
Country United States 
Sector Academic/University 
PI Contribution Collaborative experiments
Collaborator Contribution Use of their laser system: HERCULES
Impact DOIs: 10.1103/PhysRevLett.110.255002 10.1088/0741-3335/55/12/124017 10.1103/PhysRevLett.113.224801 10.1038/ncomms7747 10.1063/1.4875336
Start Year 2012
 
Description QED experiments: plasma modelling 
Organisation University of Lisbon
Department Instituto Superior Tecnico
Country Portugal 
Sector Academic/University 
PI Contribution experimental contribution
Collaborator Contribution theoretical contribution
Impact 10.1038/ncomms7747
Start Year 2014
 
Description Theoretical support 
Organisation Max Planck Society
Department Max Planck Institute for Nuclear Physics
Country Germany 
Sector Public 
PI Contribution carry out experiments in the area
Collaborator Contribution theoretical support and data interpretation
Impact Publication of high profile articles in international scientific papers. Further funding stemmed out of this collaboration. Invitation to international conferences
Start Year 2011
 
Description theoretical support: QED numerical 
Organisation University of York
Country United Kingdom 
Sector Academic/University 
PI Contribution Experimental work on high-intensity laser-matter interactions for validating numerical models
Collaborator Contribution Numerical modelling of experiments on high-intensity laser-matter interactions
Impact Ongoing experiments: no publications as yet
Start Year 2015
 
Description ABC 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact live interview with ABC Australia
Year(s) Of Engagement Activity 2016
 
Description BBC 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact live interview with BBC radio 5
Year(s) Of Engagement Activity 2016
 
Description New Scientist article 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Popular science article on my research published in the magazine New Scientist
Year(s) Of Engagement Activity 2017
URL https://www.newscientist.com/article/mg23631530-400-how-a-fiery-matterantimatter-union-may-lead-to-l...
 
Description popular science articles 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact 5 popular science articles in the "Conversation" website: more than 900000 readers online
Year(s) Of Engagement Activity 2014,2015
URL https://theconversation.com/profiles/gianluca-sarri-169569/articles
 
Description popular science in the Guardian 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Popular science article in "The Guardian"
Year(s) Of Engagement Activity 2015
URL https://www.theguardian.com/science/blog/2015/dec/11/how-to-build-a-real-lightsaber