114 documents found, page 1 of 12
Acceleration of the particle-in-cell code Osiris with graphics processing units
Lee, R. P.; Pierce, J. R.; Miller, K. G.; Almanza, M.; Tableman, A.; Decyk, V. K.; Fonseca, R. A.; Alves E. P.; Mori, W. B.Fully relativistic particle-in-cell (PIC) simulations are crucial for advancing our knowledge of plasma physics. Modern supercomputers based on graphics processing units (GPUs) offer the potential to perform PIC simulations of unprecedented scale, but require robust and feature-rich codes that can fully leverage their computational resources. In this work, this demand is addressed by adding GPU acceleration to ...
Hosing of a long relativistic particle bunch in plasma
Nechaeva, T.; Verra, L.; Pucek, J.; Ranc, L.; Bergamaschi, M.; Della Porta, G. Z.; Muggli, P.; Agnello, R.; Ahdida, C. C.; Amoedo, C.; Andrebe, Y.Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, self-modulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on ...
Particle-in-cell simulations of pulsar magnetospheres: Transition between elect...
Cruz, F.; Grismayer, T.; Torres, R.; Chen, A. Y.; Spitkovsky, A.; Fonseca, R. A.; Silva, L. O.Aims. Global particle-in-cell (PIC) simulations of pulsar magnetospheres are performed with volume-, surface-, and pair-production-based plasma injection schemes to systematically investigate the transition between electrosphere and force-free pulsar magnetospheric regimes. Methods. We present a new extension of the PIC code OSIRIS that can be used to model pulsar magnetospheres with a two-dimensional axisymmet...
OSIRIS-GR: General relativistic activation of the polar cap of a compact neutro...
Torres, R; Grismayer, T.; Cruz, F.; Fonseca, R. A.; Silva, L. O.We present ab initio global general-relativistic Particle-in-cell (GR-PIC) simulations of compact millisecond neutron star magnetospheres in the axisymmetric aligned rotator configuration. We investigate the role of GR and plasma supply on the polar cap particle acceleration efficiency – the precursor of coherent radio emission – employing a new module for the PIC code OSIRIS, designed to model plasma dynamics ...
Filamentation of a relativistic proton bunch in plasma
Verra, L.; Amoedo, C.; Torrado, N.; Clairembaud, A.; Mezger, J.; Pannell, F.; Pucek, J.; van Gils, N.; Bergamaschi, M.; Della Porta, G. Z.; Lopes, N.We show in experiments that a long, underdense, relativistic proton bunch propagating in plasma undergoes the oblique instability, which we observe as filamentation. We determine a threshold value for the ratio between the bunch transverse size and plasma skin depth for the instability to occur. At the threshold, the outcome of the experiment alternates between filamentation and self-modulation instability (evi...
RaDiO: An efficient spatiotemporal radiation diagnostic for particle-in-cell codes
Pardal, M.; Sainte-Marie, A.; Reboul-Salze, A.; Fonseca, R. A.; Vieira, J.This work describes a novel radiation algorithm designed to capture the three-dimensional, space-time resolved electromagnetic field structure emitted by large ensembles of charged particles. The algorithm retains the full set of degrees of freedom that characterize electromagnetic waves by employing the Liénard-Wiechert fields to retrieve radiation emission. Emitted electric and magnetic fields are deposited i...
Development of the self-modulation instability of a relativistic proton bunch i...
Verra, L.; Wyler, S.; Nechaeva,T.; Pucek, J.; Bencini, V.; Bergamaschi, M.; Velotti, F.; Della Porta, G. Z.; Gschwendtner, E.; Muggli, P.; Agnello, R.Self-modulation is a beam–plasma instability that is useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing the ratio between the initial transverse size of the bunch and the plasma skin depth, the instability occurs later along the bunch, or not at all, over a fixed plasma length because the amplitude of the ...
Slowdown of interpenetration of two counterpropagating plasma slabs due to coll...
Shulka, N; Schoeffler, K. M.; Vieira, J.; Fonseca, R. A.; Boella, E; Silva, L. O.The nonlinear evolution of electromagnetic instabilities driven by the interpenetration of two e-,e+ plasma clouds is explored using ab initio kinetic plasma simulations. We show that the plasma clouds slow down due to both oblique and Weibel generated electromagnetic fields, which deflect the particle trajectories, transferring bulk forward momentum into transverse momentum and thermal velocity spread. This pr...
The AWAKE Run 2 Programme and beyond
Gschwendtner, E.; Lotov, K.; Muggli, P.; Wing, M.; Agnello, R.; Ahdida, C. C.; Gonçalves, M. C. A.; Andrebe, Y.; Apsimon, O.; Apsimon, R.Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use of high energy protons to drive wakefields in plasma has been demonstrated during Run 1 of the AWAKE programme at CERN. Protons of energy 400 GeV drove wakefields that accelerated electrons to 2 GeV in under 10 m of plasma. The AWAKE collaboration is now embarking on Run 2 with the main aims to demonstra...
Interaction between electrostatic collisionless shocks generates strong magneti...
Boella, E.; Schoeffler, K. M.; Shulka, N.; Innocenti, M. E.; Lapenta, G; Fonseca, R. A.; Silva, L. O.The head-on collision between electrostatic shocks is studied via multi-dimensional particle-in-cell simulations. A strong magnetic field develops after the interaction, which causes the shock velocities to drop significantly. This transverse magnetic field is generated by the Weibel instability, which is driven by pressure anisotropies due to longitudinal electron heating while the shocks approach each other. ...