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VERSION:2.0
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PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-9837
DTSTART:20261109T180000Z
DTEND:20261109T190000Z
DTSTAMP:20261104T075534Z
LAST-MODIFIED:20261030T013458Z
LOCATION:2241 Chamberlin Hall
SUMMARY:Nonlinear Waves in Magnetized Pair Plasmas: Dispersive Shocks 
 and Sudden Dissipation\, Plasma Physics (Physics/ECE/NE 922) Seminar\,
  Pablo Bilbao\, University of Oxford
DESCRIPTION:How intense radio emission escapes neutron-star magnetosph
 eres is a central open question in the physics of pulsars and fast rad
 io bursts. In this talk\, I will investigate the nonlinear propagation
  of low-frequency extraordinary (X-mode) waves in strongly magnetized 
 electron–positron plasmas\, combining analytical drift-fluid theory 
 with particle-in-cell simulations. We show that finite-amplitude waves
  steepen into sharp cusps with a characteristic (k^{-4/3}) amplitude s
 pectrum\, before plasma dispersion transforms them into trains of soli
 tons. As the wave amplitude increases\, these solitons develop progres
 sively smaller spatial scales\, eventually breaking particle adiabatic
 ity and triggering stochastic acceleration of a small fraction of part
 icles to relativistic energies. This leads to an abrupt onset of colli
 sionless dissipation at wave amplitudes well below the conventional fl
 uid wave-breaking limit\, while most of the plasma remains cold. I wil
 l discuss how this mechanism constrains the propagation of intense ele
 ctromagnetic transients through neutron-star magnetospheres\, placing 
 limits on the coherent radio luminosity that can escape\, with implica
 tions for Crab giant pulses and fast radio bursts.
URL:https://www.physics.wisc.edu/events/?id=9837
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