SPACE AND COSMIC RAY PHYSICS SEMINAR

University of Maryland
Atlantic Building, Room 2400
4:30 PM Monday, November 15, 2010
Coffee, Tea & Snacks 4:15-4:30 PM

James Drake
University of Maryland
Is the magnetic field in the outer heliosphere laminar I:
reconnection dynamics, particle acceleration and post-reconnection bubbles

The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyagers 1 and 2 crossed the heliospheric termination shock have called into question the conventional shock source of these energetic particles. We have suggested that the sectored heliospheric magnetic field, which results from the flapping of the heliospheric current sheet, reconnects in the heliosheath.Particle-in-cell simulations reveal that most of the magnetic energy goes into the interstellar pickup ions with significant but smaller amounts of energy going into electrons and heated solar wind ions. The predicted spectra of ACRs based on this model is consistent with the Voyager observations. An important question is how to determine from the Voyager data whether the sectored magnetic field has reconnected. The question is not as simple as you might expect because the post-reconnection state of the sectored field region consistes of nested magnetic islands with a periodicity that is similar but more irregular than the unreconnected sectored field. The reconnection dynamics of the sectored field and associated particle acceleration will be discussed with an emphasis on the unusual properties of the post-reconnection nested magnetic islands and associated flows.


Sponsored by: Department of Physics and the Institute for Physical Science and Technology, University of Maryland. For information call Catha Stewart at (301) 405-4811 or go to the UMD Space Physics group seminar web site.

There is free parking after 4:00 PM in lot B (the big parking garage across the street from the ATL building). There are a limited number of spaces in lot Q next to the new ATL wing with free parking after 4PM even when there is a basketball game on campus.