Science Seminars

A Violin Sonata for Reconnection: Different Fluctuation Spectra and Turbulence Around a Reconnecting Region

Speaker: Giovanni Lapenta (KU Leuven, Belgium)
Date: Thursday, Jul 18, 2019
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

Reconnection converts magnetic energy to kinetic energy in the form of local  heating and acceleration. The state produced by reconnection includes strong sheared flows, pressure densities and anisotropies of the particle distributions. These are all sources of instability that can grow nonlinearly and lead to a state with fluctuations that result in turbulence.

I will show the results of our 3D fully kinetic (electrons and ions are particles) and deploy a new “topographical” analysis of the fluctuations to identify different regimes of reconnection. While in some regions, turbulence affects particles and fields together, in the  inflow the electromagnetic component is dominant bringing to mind Stirling Colgate’s analogy between violins, Bosch injectors in Diesel engines and astrophysical particle acceleration.

I will then focus on the energetic consequences of these fenomena, following the energy conversion and its consequences on particle acceleration.

The work discussed here received funds from NASA, from the US AirForce, from the University of Leuven and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776262 (AIDA). Computing was carried out at NASA, at NERSC (DOE) and at the EU facilities made available by consecutive Tier-0 PRACE allocations.