Astroplasmas Seminar

Next seminar

Friday, July 15th 2022, 12.30pm

Collisionless shocks in plasmas: when the density jump and the shock front do not obey MHD (at all)

Antoine Bret (Universidad de Castilla-La Mancha)

Abstract: According to MHD, a strong parallel shock is a few mean-free-paths thick, with a density jump of 4. The talk will comment on these 2 aspects for the case of a collisionless shock. First, I’ll review recent analytical works explaining how, as the plasma becomes collisionless, the front continuously switches from a few mean-free-path to a distance much shorter, in terms of the upstream plasma parameter. Second, I will also show how the density jump of a strong parallel collisionless shock can shrink to 2 instead of 4. This is due to the ability of a collisionless plasma to sustain a stable anisotropy in the presence of a magnetic field. PIC simulations will be presented confirming this conclusion.

Scheduled seminars (Fall 2021 / Spring 2022)

24 Sept: Jens Mahlmann (Princeton University)

01 Oct: Bart Ripperda (Center for Computational Astrophysics and Princeton University)

08 Oct: David Hosking (Oxford University)

15 Oct: Ben Prather (University of Illinois)

22 Oct: Tamar Faran (The Hebrew University of Jerusalem) and Luciano Combi (Instituto Argentino de Radioastronomía)

29 Oct: Aaron Tran (Columbia University) and Itai Linial (The Hebrew University of Jerusalem)

05 Nov: Lorenzo Perrone (Cambridge University)

19 Nov: Fabio Bacchini (University of Colorado)

03 Dec: Elizabeth Tolman (Institute of Advanced Studies)

10 Dec: Elias Most (Institute of Advanced Studies and Princeton University)

14 Jan: Emily Lichko (University of Arizona)

28 Jan: Wenbin Lu (Princeton University)

25 Feb: Kun Hu (Rice University)

18 Mar: Christopher Thompson (CITA)

30 Mar: Artem Bohdan (DESY)

11 Apr: Vicente Valenzuela-Villaseca (Imperial College)

15 Jul: Antoine Bret (Universidad de Castilla-La Mancha)