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91探花
Atomic and Laser Physics
Credit: Jack Hobhouse

Prof Peter Norreys FInstP;

Professorial Research Fellow

Research theme

  • Accelerator physics
  • Lasers and high energy density science
  • Fundamental particles and interactions
  • Plasma physics

Sub department

  • Atomic and Laser Physics

Research groups

  • 91探花 Centre for High Energy Density Science (OxCHEDS)
peter.norreys@physics.ox.ac.uk
Telephone: 01865 (2)72220
Clarendon Laboratory, room 141.1
  • About
  • Research
  • Teaching
  • Publications

Statistical theory of the broadband two-plasmon decay instability

(2024)

Authors:

Rusko T Ruskov, Robert Bingham, Luis O Silva, Max Harper, Ramy Aboushelbaya, Jason F Myatt, Peter A Norreys

CoordGate: Efficiently Computing Spatially-Varying Convolutions in Convolutional Neural Networks

(2024)

Authors:

Sunny Howard, Peter Norreys, Andreas D枚pp

Energy gain of wetted-foam implosions with auxiliary heating for inertial fusion studies

Plasma Physics and Controlled Fusion IOP Publishing 66:2 (2023) 025005

Authors:

Robert W Paddock, Tat S Li, Eugene Kim, Jordan J Lee, Heath Martin, Rusko T Ruskov, Stephen Hughes, Steven J Rose, Christopher D Murphy, Robbie HH Scott, Robert Bingham, Warren Garbett, Vadim V Elisseev, Brian M Haines, Alex B Zlystra, E Mike Campbell, Cliff A Thomas, Tom Goffrey, Tony D Arber, Ramy Aboushelbaya, Marko W Von der Leyen, Robin HW Wang, Abigail A James, Iustin Ouatu, Robin Timmis, Sunny Howard, Eduard Atonga, Peter A Norreys

Abstract:

Low convergence ratio implosions (where wetted-foam layers are used to limit capsule convergence, achieving improved robustness to instability growth) and auxiliary heating (where electron beams are used to provide collisionless heating of a hotspot) are two promising techniques that are being explored for inertial fusion energy applications. In this paper, a new analytic study is presented to understand and predict the performance of these implosions. Firstly, conventional gain models are adapted to produce gain curves for fixed convergence ratios, which are shown to well-describe previously simulated results. Secondly, auxiliary heating is demonstrated to be well understood and interpreted through the burn-up fraction of the deuterium-tritium fuel, with the gradient of burn-up with respect to burn-averaged temperature shown to provide good qualitative predictions of the effectiveness of this technique for a given implosion. Simulations of auxiliary heating for a range of implosions are presented in 91探花 of this and demonstrate that this heating can have significant benefit for high gain implosions, being most effective when the burn-averaged temperature is between 5 and 20鈥塳eV.

Energy gain of wetted-foam implosions with auxiliary heating for inertial fusion studies

Plasma Physics and Controlled Fusion IOP Publishing 66:2 (2023) 25005

Authors:

Rw Paddock, Ts Li, E Kim, Jj Lee, H Martin, Rt Ruskov, S Hughes, Sj Rose, Cd Murphy, Rhh Scott, R Bingham, W Garbett, Vv Elisseev, Bm Haines, Ab Zylstra, Em Campbell, Ca Thomas, T Goffrey, Td Arber, R Aboushelbaya, Mw Von der Leyen, Rhw Wang, Aa James, I Ouatu, R Timmis, S Howard, E Atonga, Pa Norreys

Abstract:

<jats:title>Abstract</jats:title> <jats:p>Low convergence ratio implosions (where wetted-foam layers are used to limit capsule convergence, achieving improved robustness to instability growth) and auxiliary heating (where electron beams are used to provide collisionless heating of a hotspot) are two promising techniques that are being explored for inertial fusion energy applications. In this paper, a new analytic study is presented to understand and predict the performance of these implosions. Firstly, conventional gain models are adapted to produce gain curves for fixed convergence ratios, which are shown to well-describe previously simulated results. Secondly, auxiliary heating is demonstrated to be well understood and interpreted through the burn-up fraction of the deuterium-tritium fuel, with the gradient of burn-up with respect to burn-averaged temperature shown to provide good qualitative predictions of the effectiveness of this technique for a given implosion. Simulations of auxiliary heating for a range of implosions are presented in 91探花 of this and demonstrate that this heating can have significant benefit for high gain implosions, being most effective when the burn-averaged temperature is between 5 and 20鈥塳eV.</jats:p>

CoordGate: efficiently computing spatially-varying convolutions in convolutional neural networks

British Machine Vision Association (2023)

Authors:

Sunny Howard, Peter Norreys, Andreas D枚pp

Abstract:

Optical imaging systems are inherently limited in their resolution due to the point spread function (PSF), which applies a static, yet spatially-varying, convolution to the image. This degradation can be addressed via Convolutional Neural Networks (CNNs), particularly through deblurring techniques. However, current solutions face certain limitations in efficiently computing spatially-varying convolutions. In this paper we propose CoordGate, a novel lightweight module that uses a multiplicative gate and a coordinate encoding network to enable efficient computation of spatially-varying convolutions in CNNs. CoordGate allows for selective amplification or attenuation of filters based on their spatial position, effectively acting like a locally connected neural network. The effectiveness of the CoordGate solution is demonstrated within the context of U-Nets and applied to the challenging problem of image deblurring. The experimental results show that CoordGate outperforms existing approaches, offering a more robust and spatially aware solution for CNNs in various computer vision applications.

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