Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

CLaSP Seminar Series - Professor John Wygant

Date: November 30, 2017
Time: 3:30 pm - 5:00 pm
Location: SRB Auditorium, room 2246

Our guest for this week's CLaSP Seminar Series will be Professor John Wygant of the University of Minnesota School of Physics and Astronomy. Please join us! 

Title: "Spacecraft studies of partitioning of Alfvenic Poynting flux into particle acceleration in different regions of the magnetosphere: the energization and associated energy flux of downward auroral electrons on the night-side and that of out-flowing energetic ions in the dayside cusp." 

Abstract: In recent years, spacecraft observations have provided strong evidence that bursts of   Poynting flux flowing down magnetic field lines towards the Earth provide an important energy input into the low altitude regions of the Earth and couple to a variety of collision-less charged particle acceleration mechanisms. In this talk, we present Poynting flux and particle energy flux measurements in order to assess the energy budget and structures of  two very different kinds of acceleration mechanisms in two different regions. One example occurring on the "night side of the Earth" is the powering by Alfvenic structures of auroral electron acceleration parallel to the magnetic field. A second acceleration mechanism occurs on the "dayside of the Earth"  on cusp magnetic field lines that connect to the solar wind. It has long been known that on cusp field lines ions are collision-lessly heated and accelerated away from the Earth by the magnetic mirror force. These extreme ion outflow events provide some of the first evidence for a "Poynting flux driven wind" flowing away from the Earth on the cusp magnetic field lines. This wind is analogous in some important ways to the solar wind, which is also believed to be driven by Poynting flux.  The dayside and nightside energy partitioning will be compared and very briefly discussed in terms of somewhat similar processes playing out in the solar corona.

Biography: John Wygant is a Professor of Physics in the School of Physics and Astronomy of the University of Minnesota. He is a space plasma experimentalist focusing on the in-situ measurement of electric fields. He is interested in magnetic field-line reconnection, auroral particle acceleration, shock waves in space, and relativistic particle acceleration in the terrestrial magnetosphere. He has been a Co-Investigator on electric field instruments which have flown on five NASA and ESA spacecraft missions and is the Principal Investigator on the Electric Field and Waves Instrument on the Van Allen Probes Mission. He has been a member of NASA advisory panels on spacecraft mission design. He is a Fellow of the American Physical Society.

Upcoming Events

November 30th
3:30 pm - 5:00 pm
CLaSP Seminar Series - Professor John Wygant
December 8th
3:00 pm - 5:00 pm
2017 Nelson W. Spencer Lecture - Professor Margaret Kivelson
December 13th
6:00 pm - 9:00 pm
Michigan Reception at AGU
December 14th
3:30 pm - 5:00 pm
Finals - No CLaSP Seminar
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