BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:“Kinetic Instabilities in Extreme Plasma Physics: Laboratory and astrophysical dynamics DTSTART:20250909T160000Z DTEND:20250909T180000Z DTSTAMP:20260807T043346Z UID:76a591b6-cf4b-4322-90cb-b8940bed6b12 SEQUENCE:2 CREATED:20250828T104304Z DESCRIPTION:Extreme plasma physics explores regimes where strong electroma gnetic fields\, intense radiation\, and quantum electrodynamics (QED) effe cts fundamentally alter the behavior of matter. These conditions are found in some of the most energetic astrophysical environments\, such as pulsar s\, black holes\, and relativistic shocks\, and are increasingly accessibl e in laboratory experiments using high-intensity lasers and particle beams . This Thesis investigates how radiation reaction\, through synchrotron an d betatron cooling\, reshapes phase space and triggers kinetic instabiliti es across a range of such extreme plasma conditions.First\, we show that s ynchrotron cooling in strongly magnetized plasmas generically leads to ani sotropic\, ringshaped momentum distributions that are unstable to the ele ctron cyclotron maser instability (ECMI). Radiation reaction sustains popu lation inversion and enables prolonged coherent emission beyond classical saturation. Second\, we demonstrate that betatron radiation in plasma wake fields produces similar structuring in high-energy beams\, forming "\; donut beams"\;"\; with pitch-angle anisotropies. These features ar e confirmed through analytical theory and largescale three-dimensional si mulations. Finally\, simulations in the context of the Fireball experiment at CERN demonstrate how relativistic electron-positron beams develop coll ective instabilities under realistic laboratory conditions\, providing the first direct analogues of astrophysical pair-plasma dynamics. Together\, these studies represent two interconnected threads of extreme plasma physi cs\, radiative cooling and pair-plasma kinetics\, and lay the groundwork f or a kinetic theory of radiatively structured plasmas\, bridging theory\, simulation\, and experiment\, and opening new paths toward probing high-en ergy astrophysical processes in the laboratory LAST-MODIFIED:20250828T104359Z LOCATION:Anfiteatro PA3 (Piso -1 do Pavilhão de Matemática) do IST URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/kinetic-instabilities-in-e xtreme-plasma-physics-laboratory-and-astrophysical-dynamics/ X-ALT-DESC;FMTTYPE=text/html:

Extreme plasma phys ics explores regimes where strong electromagnetic fields\, intense radiati on\, and quantum electrodynamics (QED) effects fundamentally alter the beh avior of matter. These conditions are found in some of the most energetic astrophysical environments\, such as pulsars\, black holes\, and relativis tic shocks\, and are increasingly accessible in laboratory experiments usi ng high-intensity lasers and particle beams. This Thesis investigates how radiation reaction\, through synchrotron and betatron cooling\, reshapes p hase space and triggers kinetic instabilities across a range of such extre me plasma conditions.

First\, we show that synchrotron cooling in strongly magnetized plasmas generically leads to anisotropic\, ringshape d momentum distributions that are unstable to the electron cyclotron maser instability (ECMI). Radiation reaction sustains population inversion and enables prolonged coherent emission beyond classical saturation. Second\, we demonstrate that betatron radiation in plasma wakefields produces simil ar structuring in high-energy beams\, forming "\;donut beams"\;&qu ot\; with pitch-angle anisotropies.

These features are confirmed through analytical theory and largescale three-dimensional simulations. Finally\, simulations in the context of the Fireball experiment at CERN de monstrate how relativistic electron-positron beams develop collective inst abilities under realistic laboratory conditions\, providing the first dire ct analogues of astrophysical pair-plasma dynamics. Together\, these studi es represent two interconnected threads of extreme plasma physics\, radiat ive cooling and pair-plasma kinetics\, and lay the groundwork for a kineti c theory of radiatively structured plasmas\, bridging theory\, simulation\ , and experiment\, and opening new paths toward probing high-energy astrop hysical processes in the laboratory

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