[IGPP Everyone] Reminder - Friday - EPSS Space Physics seminar announcement - Friday November 19, 2021 - 03:30 PM Pacific Time (US and Canada)

[Sowmendran, Margie (IGPP)]

R E M I N D E R - F R I D A Y - 11/19/2021

SPACE PHYSICS SEMINAR

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES
DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES
UNIVERSITY OF CALIFORNIA, LOS ANGELES

ZOOM LINK PROVIDED BELOW

 https://ucla.zoom.us/j/92101918782?pwd=Z2o5RmI4OEpBWW4zcG1DZStIUWgrZz09




Efficient non-thermal particle acceleration mediated by the kink instability in jets
Professor Paulo Alves,
Physics and Astronomy, UCLA



Astrophysical jets shine across the entire electromagnetic spectrum and are among the most powerful particle accelerators in the universe. Yet, the mechanisms underlying their particle acceleration are not well understood. MHD simulations suggest that the development of the current-driven kink instability (KI) can play an important role in the dissipation of the jet's internal magnetic field, but it remains clear if such process could lead to efficient non-thermal particle acceleration, required to explain observations. In this talk, I will present 3D particle-in-cell simulations that capture the self-consistent particle acceleration associated with the development of the current-driven kink instability (KI) in magnetic field geometries relevant to recollimation regions of relativistic jets. These simulations reveal that the development of the KI mediates the efficient dissipation of the magnetic field into high-energy particles. Non-thermal particles are accelerated by a coherent inductive electric field that develops at the core of the current flow during the nonlinear stage of the KI. Acceleration by the large-scale inductive electric field is made efficient by the highly tangled magnetic field structure that characterizes the nonlinear phase of the KI, which allows particles to experience rapid curvature-drift motions across the magnetic field lines and parallel to the electric field. This results in a spectral power-law tail that is robust for a large range of initial conditions and system sizes. I will present scaling laws for this process with system size and magnetization, and discuss the implications of our results for relativistic astrophysical jets. Finally, I will discuss the possibility of exploring this physics in high-energy-density (HED) laboratory experiments.



Friday, November 19,  2021
3:30 - 5:00 PM

In-Charge:  Marco Velli

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