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:20260814T212949Z UID:76a591b6-cf4b-4322-90cb-b8940bed6b12 SEQUENCE:1 CREATED:20250828T104250Z DESCRIPTION: Extreme plasma physics explores regimes where strong electrom agnetic fields\, intense radiation\, and quantum electrodynamics (QED) ef fects fundamentally alter the behavior of matter. These conditions are fo und in some of the most energetic astrophysical environments\, such as pu lsars\, black holes\, and relativistic shocks\, and are increasingly acces sible in laboratory experiments using high-intensity lasers and particle beams. This Thesis investigates how radiation reaction\, through synchrot ron and betatron cooling\, reshapes phase space and triggers kinetic inst abilities across a range of such extreme plasma conditions.First\, we show that synchrotron cooling in strongly magnetized plasmas generically lead s to anisotropic\, ringshaped momentum distributions that are unstable to the electron cyclotron maser instability (ECMI). Radiation reaction sust ains population inversion and enables prolonged coherent emission beyond classical saturation. Second\, we demonstrate that betatron radiation in p lasma wakefields produces similar structuring in high-energy beams\, form ing "\;donut beams"\;"\; with pitch-angle anisotropies. These features are confirmed through analytical theory and largescale three-di mensional simulations. Finally\, simulations in the context of the Firebal l experiment at CERN demonstrate how relativistic electron-positron beams develop collective instabilities under realistic laboratory conditions\, providing the first direct analogues of astrophysical pair-plasma dynami cs. Together\, these studies represent two interconnected threads of extr eme plasma physics\, radiative cooling and pair-plasma kinetics\, and lay the groundwork for a kinetic theory of radiatively structured plasmas\, b ridging theory\, simulation\, and experiment\, and opening new paths towa rd probing high-energy astrophysical processes in the laboratory LAST-MODIFIED:20250828T104250Z LOCATION:Anfiteatro PA3 (Piso -1 do Pavilhão de Matemática) do IST URL:http://df.vps.tecnico.ulisboa.pt/en/events/kinetic-instabilities-in-ex treme-plasma-physics-laboratory-and-astrophysical-dynamics/ X-ALT-DESC;FMTTYPE=text/html:

Extreme plasma phy sics explores regimes where strong electromagnetic fields\, intense radia tion\, and quantum electrodynamics (QED) effects fundamentally alter the b ehavior of matter. These conditions are found in some of the most energet ic astrophysical environments\, such as pulsars\, black holes\, and relat ivistic shocks\, and are increasingly accessible in laboratory experiment s using high-intensity lasers and particle beams. This Thesis investigates how radiation reaction\, through synchrotron and betatron cooling\, resh apes phase space and triggers kinetic instabilities across a range of suc h extreme plasma conditions.

First\, we show that synchrotron co oling in strongly magnetized plasmas generically leads to anisotropic\, ri ngshaped momentum distributions that are unstable to the electron cyclotr on maser instability (ECMI). Radiation reaction sustains population inver sion and enables prolonged coherent emission beyond classical saturation. Second\, we demonstrate that betatron radiation in plasma wakefields pro duces similar structuring in high-energy beams\, forming "\;donut beam s"\;"\; with pitch-angle anisotropies.

These features a re confirmed through analytical theory and largescale three-dimensional s imulations. Finally\, simulations in the context of the Fireball experime nt at CERN demonstrate how relativistic electron-positron beams develop co llective instabilities under realistic laboratory conditions\, providing the first direct analogues of astrophysical pair-plasma dynamics. Togethe r\, these studies represent two interconnected threads of extreme plasma physics\, radiative cooling and pair-plasma kinetics\, and lay the ground work for a kinetic theory of radiatively structured plasmas\, bridging the ory\, simulation\, and experiment\, and opening new paths toward probing high-energy astrophysical processes in the laboratory

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