Irreversible heating in collisionless plasmas

Nuno Loureiro

MIT-PSFC

Friday, April 15, 2016

3:00pm

NW17-218

PSFC Seminars

Abstract: Nonlinear energy transfer and dissipation in magnetized plasmas is a fundamental open problem whose resolution is vital to the understanding of kinetic turbulence and magnetic reconnection. In many laboratory, space and astrophysical plasmas of interest, the collisional times are much longer than the dynamical timescales associated with turbulence and/or reconnection (i.e., the plasmas are collisionless); however, collisions must play a role in order for the energy dissipation – heating of ions and electrons – to become irreversible. The exact details of how this happens as a function of plasma parameters must account for the different ion to electron heating ratios that are observed, and for temperature anisotropies, which themselves may lead to dynamically important instabilities.  

This talk will explore these questions mainly in the context of a recently derived formalism, reduced-gyrokinetics, which allows for a straightforward spectral (Hermite) representation of velocity-space. This enables very detailed investigations of energy phase-space dynamics, and may, in some cases, point the way to relatively simple fluid closures that greatly reduce the computational cost of this type of problem.

Bio: Nuno Loureiro obtained his PhD in Physics from Imperial College London in 2005.  He then worked as a post-doctoral researcher at the Princeton Plasma Physics Laboratory for two years, after which he moved to the Culham Centre for Fusion Energy in the UK as a Fusion Research Fellow. In 2009 he was hired as an Assistant Researcher at the Institute for Plasmas and Nuclear Fusion in Lisbon, Portugal. There, he became Head of Theory and Modeling in 2012, and Principal Investigator in 2014. He recently moved to MIT for an Assistant Professor position with the Nuclear Science and Engineering Department. Nuno is the 2015 recipient of the Thomas H. Stix award of the American Physical Society for outstanding early career contributions to plasma physics research.