Key physics for Inertial Confinement Fusion diagnosed by ion emission

Lead Research Organisation: University of Strathclyde
Department Name: Physics

Abstract

We propose a new programme of research which will provide substantial and important advances in our understanding of the physics of energetic electron transport and shock breakout uniformity in dense plasma - processes critical to the success of Inertial Confinement Fusion (ICF) schemes. We will do this by developing an entirely new class of diagnostic, based on ion emission, and apply this to diagnose electron transport and shock uniformity breakout with unprecedented micron-scale resolution. This offers significant advantages over existing diagnostic techniques and when combined with existing techniques will greatly increase our understanding of key physical processes for ICF.ICF holds the promise of achieving conditions in the laboratory where more energy is produced in fusion reactions than is incident on an imploding fusion pellet, thus creating an energy source (Inertial Fusion Energy). A critical issue for the fast ignition approach to ICF is the efficient delivery of energy from a short 'ignition' laser pulse, usually by acceleration and transport of energetic electrons. An understanding of energy transport and heating by laser-accelerated relativistic electrons is therefore of fundamental importance to the fast ignitor concept and yet there are many outstanding physics questions relating to this. The transport of fast electrons through dense matter is also important for the development of high power laser driven ion sources. The research proposed here involves a comprehensive programme of experimental investigations, underpinned by theoretical modelling, designed to address questions on electron transport and shock propagation of fundamental importance to the development of laser driven particle and radiation sources in general and ICF in particular.The programme will be carried out using state-of-the-art high intensity laser systems at the Central Laser Facility, Rutherford Appleton Laboratory.

Publications

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Carroll D (2010) A modified Thomson parabola spectrometer for high resolution multi-MeV ion measurements-Application to laser-driven ion acceleration in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

 
Description This research project focused on the physics of energetic electron generation and transport in dense targets irradiated by ultraintense laser pulses. The results are important for almost all topics in the field of high intensity laser-solid interactions, and are of particular importance in the development of advanced approaches to inertial confinement fusion and for laser-driven schemes for the production of high energy ion beams. The project has resulted in 43 papers in leading international peer-reviewed journals, including several in Physical Review Letters, and numerous invited presentations at national and international conferences and workshops.
A highlight of our research programme was the first demonstration that lattice structure plays an important role in defining the properties of beams of energetic electrons transported in solids irradiated by ultrashort high intensity laser pulses. We determined that by heating solids fast enough it is possible to create highly non-equilibrium states of warm dense matter in which the electrons in the material are thermally excited but the ions temporarily remain cold and retain their lattice structure, and that the electrical conductivity of the material in this transient state strongly affects energetic electron transport. The experiment was performed using high-power laser pulses from the Vulcan petawatt laser at the UK's Central Laser Facility and our findings are supported by detailed theoretical work. The result has implications for the many potential applications of high power laser-solid interactions, e.g. impacting on the choice of materials used in the fabrication of advanced targets for fusion and in targets for laser-driven ion acceleration. Our finding that diamond produces smooth electron transport is particularly interesting from an applications viewpoint because of its unique material properties, including high hardness and thermal conductivity.
Other pioneering work resulting from this research programme includes demonstration of the effects of self-generated magnetic fields on the propagation of energetic electron beams in homogeneous solids and a new technique for guiding energetic electrons in layered solid targets irradiated by ultra-intense laser pulses. Strong magnetic fields created at the interface of two different metals are used to guide the transport of energetic electrons through dense plasma. This approach could impact on the design of targets to achieve the fast ignition approach to inertial fusion energy.
Other highlights include important new understanding of the processes giving rise to the guiding of energetic electrons laterally along target surfaces, and specifically the sensitivity of these processes to various laser and target parameters. The effects of circulating energetic electrons within solids on X-ray emission was demonstrated for the first time and a comprehensive set of measurements on the effects of preformed plasma on laser energy absorption and coupling to energetic electrons was made as part of this research project. These results have led to new schemes for enhancing laser energy coupling to electrons and ions and for controlling the properties of laser-accelerated ion beams.
Exploitation Route The outcomes of this work impacts the development of advanced high gain approaches to inertial confinement fusion and thus the potential for inertial fusion energy. They also impact strongly on the development of laser driven ion acceleration (in particularly on acceleration mechanisms involving sheath fields produced by energetic electrons transported through solids). The outcomes will be taken forward primarily by researchers working on these topics. The outcomes are also informing research into the development of laser-driven ion acceleration, the potential applications of which include the healthcare sector.
Sectors Energy,Healthcare

 
Description The non-academic beneficiaries of this research are the general public and industry. Results from this project are being used to inform the development of laser-driven ion and radiation (X-ray) sources. There are many potential applications of these sources being actively pursued. One of the most exciting and widely-discussed possibilities is to use potentially compact laser-ion sources for hadron therapy/oncology. The outcomes are also benefiting the international effort to develop advanced high gain approaches to inertial confinement fusion and thus inertial fusion energy. For example, an international research group have started investigating diamond targets for advanced approaches to ignition based on the outcomes of our research into the fast electron transport properties of diamond. Thus the findings of this research project are likely to benefit society via applications in health and energy in the long term. There are also potential long term benefits to UK industry via the development of laser-driven radiation sources (for applications such as ion implantation). The project resulted in the training of a post-doctoral researcher and two PhD researchers, with a range of skills valued by both academia and industry.
 
Description EPSRC
Amount £1,330,510 (GBP)
Funding ID EP/J003832/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start  
 
Description Central Laser Facility 
Organisation ELI Beamlines
Country Czech Republic 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Extreme Light Infrastructure - Nuclear Physics (ELI-NP)
Country Romania 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Helmholtz Association of German Research Centres
Department GSI Helmholtz Centre for Heavy Ion Research
Country Germany 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Central Laser Facility 
Organisation Rutherford Appleton Laboratory
Department Central Laser Facility
Country United Kingdom 
Sector Public 
PI Contribution I am a user of high power laser facilities provided by these partners
Collaborator Contribution Provision of laser beam time
Impact Multiple research publications
Start Year 2012
 
Description Joint research with CCLRC (Council for Central Laboratory of Research Councils) 
Organisation The Chronic Granulomatous Disorder Society
Department Chronic Granulomatous Disorder (CGD) Research Trust
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution University of Strathclyde researchers worked on this project with researchers from CCLRC (Council for Central Laboratory of Research Councils)
Start Year 2007
 
Description Advanced Highers School Outreach event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact n/a
Year(s) Of Engagement Activity 2011
 
Description Advanced Highers School Outreach event 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Speaker : Schools engagement.
Year(s) Of Engagement Activity 2011
 
Description An overview of laser-driven ion acceleration 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2008
 
Description An overview of laser-driven ion acceleration 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2008
 
Description Effects of plasma expansion on laser-driven proton acceleration 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2008
 
Description Effects of plasma expansion on laser-driven proton acceleration. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2008
 
Description Fast electron generation and transport in high power laser solid interactions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2010
 
Description Fast electron generation and transport in high power laser solid interactions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2010
 
Description Harnessing fusion energy using lasers 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Speaker : Public lecture/debate/seminar.
Year(s) Of Engagement Activity 2010
 
Description Investigation of plasma critical surface dynamics in intense laser-solid interactions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Contributor : Invited talk.
Year(s) Of Engagement Activity 2011
 
Description Invited speaker -Summer School "Towards Fusion Energy", Poland (2011) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Invited speaker -Summer School "Towards Fusion Energy", Poland (2011)
Year(s) Of Engagement Activity 2011
 
Description Invited speaker -Summer School "Towards Fusion Energy", Poland (2011) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk : Invited speaker -Summer School "Towards Fusion Energy", Poland (2011).
Year(s) Of Engagement Activity 2011
 
Description Laser energy transfer to fast electrons in solid targets 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2009
 
Description Laser energy transfer to fast electrons in solid targets 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience
Results and Impact Visitor : Invited talk.
Year(s) Of Engagement Activity 2009
 
Description Progress in laser driven ion source development 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Presenter : Public lecture/debate/seminar.
Year(s) Of Engagement Activity 2010
 
Description Prospects for Inertial Fusion Energy 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact n/a
Year(s) Of Engagement Activity 2011