Physics Department Colloquia
Events on Friday, February 17th, 2017
- The basic physics of collisionless magnetic reconnection
- Time: 3:30 pm
- Place: 2241 Chamberlin hall
- Speaker: Michael Hesse, NASA & Birkeland Centre for Space Science
- Abstract: Magnetic reconnection is a plasma process, which enables, by means of highly localized physics, the often-explosive release of stored magnetic energy over very large spatial scales. Magnetic reconnection is believed to play a key role in the dynamics of plasmas in a diverse multitude of environments, which include pulsar magnetospheres on one end, and laboratory plasmas on the other. Owing both to this universality and to the impact of reconnection, the underlying physics has been a target or research for quite some time. However, only the advent of advanced computer simulations and, most recently, the revealing space observations of the Magnetospheric Multiscale (MMS) mission have facilitated breakthroughs in our understanding of the critical local physics in the so-called diffusion region. This talk will present recent research results pertaining to the diffusion region. As an introduction, we will review the role reconnection plays as an energy release and conversion process, and briefly look at a variety of applications. We will then focus on reconnection at the Earth’s magnetopause, and will investigate in detail a high-precision numerical simulation of reconnection in this environment. Thereafter, we will look into the role of the reconnection electric field in sustaining the current flow in the inner diffusion region. We will end by demonstrating that complex particle behavior, which leads to population mixing and an effective, thermal, inertia, is critical aspect of this region.
- Host: Jan Egedal