During the academic semesters the plasma physics department hosts seminars on Tuesday at 2:30 pm.
If you have questions or want to suggest a speaker/topic, please contact Prof. Olga Rosmej or Dr. Paul Neumayer.

Plasmaphysik Seminar

Growth of concomitant laser-driven collisionless and resistive electron filamentation instabilities over large spatiotemporal scalesONLINE ONLY

by Charles Ruyer (CEA)

Europe/Berlin
Online

Online

Zoom-Meeting https://gsi-fair.zoom.us/j/96629963798 Meeting-ID: 966 2996 3798 Kenncode: 130302
Description

Collective processes in plasmas often induce micro-instabilities that play an important role in many space or laboratory plasma environments. Particularly notable is the Weibel-type current filamentation instability, which is believed to drive the creation of collisionless shocks in weakly magnetized astrophysical plasmas. Here, this instability class is studied through interactions of ultraintense and short laser pulses with solid foils, leading to localized generation of MeV electrons. Proton radiographic measurements of both low- and high-resistivity targets show two distinct, superimposed electromagnetic field patterns arising from the interpenetration of the MeV electrons and the background plasma. Particle-in-cell simulations and theoretical estimates suggest that the collisionless Weibel instability building up in the dilute expanding plasmas formed at the target surfaces causes the observed azimuthally symmetric electromagnetic filaments. For a sufficiently high resistivity of the target foil, an additional resistive instability is triggered in the bulk target, giving rise to radially elongated filaments. The data reveal the growth of both filamentation instabilities over large temporal (tens of picoseconds) and spatial (hundreds of microns) scales.

[1] C. Ruyer, S. Bolaños, B. Albertazzi et al., Nature Physics 16, 983–988 (2020)

Organized by

Paul Neumayer