NCAT PHYSICS COLLOQUIUM SIRIES
2007/2008
Contact: Dr. Abebe Kebede
336-285 2113 or email abkebede@gmail.com






  Dr. Fred Hall







Fred Hall IV, Ph.D
Postdoctoral Fellow of Space Physics
 Department of Physics and Astronomy
   University of North Carolina at Chapel Hill
Email: hallf@physics.unc.edu
Web:http://www.physics.unc.edu
September 8, 2008
Marteenal Hall Room 310  Monday 4:00 PM

Title: Numerical Simulation of a Mechanism
for Current Sheet Thinning in the Growth Phase of Magnetospheric Substorms

ABSTRACT

The magnetospheric substorm may be considered to be a "fundamental unit" of the dynamics of the terrestrial magnetosphere,
the region of space dominated by Earth's intrinsic magnetic field that is formed through the interaction of that magnetic field with the solar wind.  A `classical' substorm occurs when the normal exchange of mass, momentum, and energy between the solar wind and the magnetosphere is enhanced.  A portion of the bulk kinetic energy incident upon the dayside magnetosphere is converted into magnetic field energy and stored during the growth phase of the substorm.  This stored energy is then "explosively" released during the expansion phase of the substorm.  The thinning of the current sheet in the near-Earth magnetosphere that is observed toward the end of the growth phase establishes the conditions for the onset of the expansion phase. I discuss work arguing that this current sheet thinning results from the evacuation of a `magnetic flux reservoir' in the near-Earth magnetotail to replace magnetic flux that is eroded on the dayside of the magnetosphere by magnetic reconnection. Numerical modeling of this process is presented to support this hypothesis.

Notes

Level: Advanced Undergraduate and above
Courses related to the subject: Electromagnetism,  Electromagnetics, Statistical Physics, fluid dynamics, Magnetohydrodynamics, Atmospheric Physics, Plasma Physics, Aerospace engineering, high frequence radio communication, computational science and engineering, upper atmospheric chemistry, aurora phenomenon, Sun-Earth connections and many more


Astronomy and Space at NC A&T-Physics