In a paper recently published in the prestigious journal Physical Review Letters, entitled “Mitigation of the Onset of Hosing in the Linear Regime through Plasma Frequency Detuning”, a research team from IST, in collaboration with the Max Planck Institute for Physics in Germany, proposes a solution to a problem that threatens one of the existing concepts for a plasma-based particle accelerator. The problem consists of an instability that can develop when a particle beam propagates in plasma and is subject to the associated electric fields, which can be extremely strong, resulting in its potential disruption. This work is led by the Physics Department (DF) PhD student Mariana Moreira, under the supervision of Prof. Jorge Vieira from DF and GoLP/IPFN.
Plasma-based particle acceleration promises the emergence of much more compact and potentially cheaper accelerators. This idea was first put forward in 1979, and since then different possibilities of realizing the…

Following our tradition (see the “2014 Natas”, “2015 Natas”, “2016 Natas”, “2017 Natas”, “2018 Natas“ and “2019 Natas“), the prizes for the winners of the image, video, and VR of 2023, the “natas” of visualization, are finally announced.
The prizes awarded were:

Best image: Róbert Babjak and Rui Torres (tie)
Best video: Camilla Willim
Best VR visualization: Camilla Willim and Bertrand Martinez (tie)

The term “Nata” was coined by one of the previous winners Paulo Alves: “Nata” is a tasty Portuguese pastry that everybody likes. It’s as enjoyable as having our simulations running nicely on a big supercomputer. It can also mean being at the top, at a high level, important.” Nata is also a new open-source visualization framework recently launched by epp team members. Many congratulations to the 2023 winners! The images and videos have been posted on the team website here and will be posted over…

The work “Creation and direct laser acceleration of positrons in a single stage” by EPP members Martinez B, Barbosa B, and Vranic M. is now out in the journal Physical Review Accelerators and Beams. In this paper, they propose a new setup to obtain relativistic positron beams using next-generation laser systems.
Positrons are created and accelerated during the interaction of an intense laser pulse (80 PW, and 12 kJ of energy) with a relativistic electron beam at 90 degrees of incidence, as seen in the Figure. In this work, it is proven that direct laser acceleration is responsible for the energy enhancement of the positrons.

In a new article in the newspaper Publico, Luis OS (GoLP/IPFN) writes about what to expect from nuclear fusion in the near future and what role can Técnico researchers play in this process.

(translated) «But now everything will be easier because we are aware of what is the final goal (and that is possible to reach it). I dare to expect (and bet!) that, in the next two years, further improvements will be achieved now from the side of nuclear fusion from magnetic confinement, with the demonstration of an energy gain bigger than one (bigger energy produced than the one injected)»

 full article at:  bit.ly/3w8l64G

The work “Machine-learning-based models in particle-in-cell codes for advanced physics modules” by EPP members Chiara B, Pablo J. B., Fábio C, and Luis OS is now out on Journal of Plasma Physics. This paper proposes a new method to use ML-based models in state-of-the-art plasma codes. ML models can be used in these codes to speed up or replace costly sub-algorithms typically used in advanced physics modules.
To showcase the method, the calculation of the probability of interaction between particles via collisions has been replaced, leading to an increase in computational performance without significant physics deterioration (see the plot shared here) from the classical algorithm.

On Wednesday, 21st of December at 2:30 am, there will be our next GoLP VIP Seminar by Prof. E. Paulo Alves (University of California, Los Angeles). The event will take place at Anfiteatro Abreu Faro – Complexo I at IST.
Title: Accelerating our understanding of complex nonlinear plasma dynamics using machine learning
Abstract: The increasing quantity and quality of plasma data being produced by laboratory experiments, spacecraft observations and high-fidelity numerical simulations is creating new opportunities for innovation in the way we do plasma physics. In particular, deep learning techniques are offering powerful new ways of building highly predictive data-driven models for various important applications (including disruption prediction of fusion plasmas). The inherent complexity of these data-driven models, however, limits their interpretability, challenging the development of a theoretical understanding of the plasma physics underlying the data. In this talk, I will focus on how sparse regression techniques can be used to infer interpretable plasma physics models…

EPP members (in the first picture) Petr V, Camilla W, Thales S, and Luis OS went to Tel-Aviv (Israel) to attend the Conference on High Intensity Laser and attosecond science, held on 5th-7th of December 2022. Luis OS and Camilla W presented a talk about their recent work, and Thales S and Petr V presented a poster.

Bertrand M went to Hico, Gyeongju (Korea) to attend the 20th International Congress on Plasma Physics, held from the 27th of November to the 2nd of December, and presented a talk about his recent work.
 
 

Jorge V was awarded with the ULisboa/CGD Scientific Prize (Physics and Materials category) on November 28th. The scientific prize was institutionalized by the University of Lisbon in collaboration with Caixa Geral de Depósitos, and they distinguish scientific research activities as an incentive to publish in high impact international scientific journals.

EPP members Bernardo M and Miguel P went to Hyatt Regency Long Island, Hauppauge (NY) to attend 20th Advanced Accelerator Concepts Workshop (AAC’22), held on 6-11 November 2022, and presented a talk about their recent work.