Thomas Grismayer has been awarded a prestigious FCT Investigator contract in this year’s extremely competitive contest for these new positions.
Thomas obtained a Starting Grant for his proposal title “Pair dominated plasmas in ultra intense fields: from the laboratory to astrophysics.” The central scientific questions and the research focus of this project will be to determine the conditions for the creation of pair plasmas in the laboratory under the action of ultra intense fields (magnetic field and/or laser pulses) and to investigate the self-consistent collective dynamics of such plasmas with their radiation, both in laboratory and astrophysical conditions such as pulsars and magnetars.
The central scientific questions and the research focus of this project will be to determine the conditions for the creation of pair plasmas in the laboratory under the action of ultra intense fields and the determination of the role of the self-consistent collective dynamics of such plasmas, both…

The paper “The impact of kinetic effects on the properties of relativistic electron-positron shocks” by Anne Stockem et al. (2012) was published in Plasma Physics and Controlled Fusion, vol. 54, p. 125004. We show that the transition from a cold upstream to a hot downstream determines the steady state solution of the shock, with deviations of 10% from the standard MHD model. This allows for a quantitative definition of the shock transition region. More information and the full text of the paper can be found here.

The Partership for Advanced Computing in Europe (PRACE) awarded 45 Million core-hours to a EPP researchers team lead by J. Vieira to explore ultra-relativistic beam plasma interactions from miniatured plasma based accelerators to extreme astrophysical conditions. This proposal then aims at exploiting our simulation infrastructure to advance knowledge of next-generation plasma based accelerators driven by ultra-relativistic lepton and hadron bunches. This award is critical to address key open challenges of proton driven plasma wakefield acceleration experiments at CERN and for the design of lepton self-modulation experiments at SLAC. Another key aim of this award is to explore new plasma physics phenomena relevant for astrophysics and to investigate novel configurations allowing to mimic extreme astrophysical conditions in the laboratory.

On the issue 11, pp 2503-2514 of Computer Physics Communications, X. Xu et al published their research on numerical instabiliy due to relativistic plasma drift in EM-PIC simulations. In this paper, we show that a numerical instability arises from the intersection of beam resonances and electromagnetic modes in the drifting plasma. Spectral filters were applied in order to suppress this instability, which is critical to model extreme astrophysical scenarios such as the onset of relativistic shocks and plasma based accelerators in boosted frames. More information and the full text of the paper can be found .

On the issue 20, 064501 of Physics of Plasmas, G. Genoud et al published their work on measurements of the effect of focal spot quality on self-guided laser wakefield accelerators. In this paper, we show that by controlling the focal spot quality with a deformable mirror, it is possible to increase the fraction of pulse energy contained within the central part of the focal spot, enhancing the amount of energy transfered to the plasma wakefield and to the accelerated electrons. More information and the full text of the paper can be found here.

“dc-Magnetic-Field Generation in Unmagnetized Shear Flows” by Thomas Grismayer et al. was published in Physical Review Letters. It describes the mechanism, intrisic to shear gradients on the electron scale, of the generation of dc magnetic fields. The dc magnetic fields in unmagnetized electron-ion shear flows is shown to be associated to either initial thermal effects or the onset of electron-scale shear instabilities, in particular the cold Kelvin-Helmholtz instability. More information can be founded here.
 

Fig. 1 – Bz component of the magnetic-field structure generated by the cold KHI for v0=0.2c during (a) the linear regime, (b) near saturation, and (c) at wpe*t =1000. The insets on the right hand side represent the longitudinal average of the magnetic field, revealing the dc component.

The paper “Relativistic generalization of formation and ion-reflection conditions in electrostatic shocks” by Anne Stockem et al. (2013) was published in Physical Review E, vol. 87, p. 043116. In this paper, we generalize the model for electrostatic shock formation for relativistic electron temperatures and discuss the effects of a non-zero ion temperature on the reflection condition. We find that, due to the relativistic effects, the ions are reflected with lower energies. More information and the full text of the paper can be found here.

 
PhD student Paulo Alves has been awarded one of this year’s Gulbenkian Prizes for Stimulus to Scientific Research, in the area of Physics/Advanced Materials, with his work “Ab initio nonlinear electromagnetic metamaterials”.
Paulo’s research centers on the exciting new field of electromagnetic metamaterials: artificial materials which can bend and manipulate light in extraordinary ways. These materials can be engineered to produce exotic effects, like guiding light around an object rendering it invisible, or even focusing light beyond the limits of conventional lenses, acting as a super lens.
The remarkable properties of metamaterials have attracted a great deal of scientific and technological interest. “I am interested in understanding how light behaves under very bizarre conditions found in metamaterials, like negative refraction, from a fundamental level”, says Paulo. “In particular, I would like to understand how high intensity light interacts with metamaterials, to investigate nonlinear effects in unusual conditions”.
 

 
Figure: Cherenkov emission…

Investigadores do Instituto de Plasmas e Fusão Nuclear (IPFN), Instituto Superior Técnico e do Lawrence Livermore National Laboratory (LLNL) dos E.U.A. correram simulações recorde usando a totalidade dos 1 572 864 cores do supercomputador Sequoia localizado no laboratório americano. Este computador, baseado na arquitetura IBM BlueGene/Q é a primeira máquina a utilizar mais de um milhão de cores de computação. É também atualmente a segunda máquina na lista dos supercomputadores mais rápidos do mundo, atingindo um desempenho de 16,3 Petaflops (16,3 × 1015 = 16,3 milhares de biliões de operações matemáticas por segundo).
 

 
O código de simulação utilizado foi o código OSIRIS, desenvolvido no Grupo de Lasers e Plasmas do Instituto de Plasmas e Fusão Nuclear do IST, no âmbito duma colaboração de mais de uma década com a Universidade da Califórnia em Los Angeles. Nestas simulações o OSIRIS demonstrou uma excelente escalabilidade paralela na utilização da totalidade dos 1,6…

PhD candidate Frederico Fiuza (GoLP/IPFN), won the 2011 Oscar Buneman Award for Best Scientific Visualization, delivered at the 22nd International Conference on Numerical Simulation of Plasmas, held recently in New Jersey, USA .
The Oscar Buneman Award, created in memory of one of the pioneers of numerical simulation of plasmas, is awarded every two years to the scientific visualization work that best contributes to the understanding of plasma physics.
This year’s winning work illustrates for the first time the possibility of studying in the laboratory extreme astrophysical scenarios associated with relativistic shock waves and the acceleration of cosmic rays. These impressive natural events can be reproduced through the interaction of intense lasers with plasmas.
Shock waves are perturbations that move faster than the speed of sound in a given environment. In astrophysics, they can even reach speeds approaching the speed of light – for instance, during the violent explosion of massive stars,…