Computing Division Cross-Disciplinary Seminars (2025)

1 Jan 2025, 06:00 → 31 Dec 2025, 20:00 Europe/London

Culham/Remote

Aravinda Perera (Plasma Simulation)

The monthly Computing Division Cross-Disciplinary Seminars complement the Computing Division Technical Meetings.

They are intended to provide a spotlight to invite external speakers working on both new and well-established 

• computational methods,
• frameworks,
• software,
• practices,
• and other advancements

in non-fusion fields and sectors, or within groups working in fusion but are not currently collaborating with UKAEA, and could be of interest to the UKAEA computing community.

These seminars are normally recorded. Recordings of previous seminars can be found here:

Computing Division Cross-Disciplinary Seminar recordings

Recordings of past seminars

Tuesday 25 March

15:00 → 16:00 Numerical Methods: Energy-preserving coupling of explicit particle-in-cell with Monte Carlo collisions

Convener: Aravinda Perera (Plasma Simulation)

15:00 Energy-preserving coupling of explicit particle-in-cell with Monte Carlo collisions

Abstract
The particle-in-cell (PIC) and Monte Carlo collisions (MCC) methods are workhorses of many numerical simulations of physical systems. Recently, it was pointed out that, while the two methods can be exactly—or nearly—energy-conserving independently, combining the two leads to anomalous numerical heating. This paper reviews the standard explicit PIC-MCC algorithm, elucidates the origins of the anomalous numerical heating, and explains how to couple the two methods such that the anomalous numerical heating is avoided.

Biography
Jean-Luc Vay is a senior scientist and head of the Advanced Modeling Program in the Accelerator Technology and Applied Physics Division at Lawrence Berkeley National Laboratory. His research interests include the development and application of high-performance simulation tools and artificial intelligence methods to the modeling of particle and laser beams, plasmas, particle accelerators and fusion energy devices. He received a BA in Physics from the University of Poitiers, France, and an MS and a PhD in Physics from the University of Paris, France.

Dr. Vay has made significant contributions to particle-in-cell (PIC) methods, notably pioneering the Lorentz-boosted-frame technique (https://doi.org/10.1103/PhysRevLett.98.130405), which mitigates disparities of time and length scales between mutually relativistic particle populations, and the E-cross-B drift-preserving Boris integrator that is now known as the 'Vay push' (https://doi.org/10.1063/1.2837054). He was part of the international teams awarded the 2022 ACM Gordon Bell Prize and the 2025 DOE Secretary of Energy Achievement Award for work developing the AMR-capable Exascale PIC code WarpX (https://doi.org/10.1109/SC41404.2022.00008).

Speaker: Dr Jean-Luc Vay (LBNL)

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Paper: Energy-preserving coupling of explicit particle-in-cell with Monte Carlo collisions

Recording