Surname: Barakat
First Name: Abdallah
Status= other
Institution: Utah State University
E-mail: arb@theory.cass.usu.edu
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Title: 
The Role of Wave-Particle Interactions on Ionosphere-Magnetosphere Coupling
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Authors: 
A. R. Barakat and R. W. Schunk
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Abstract: 

	In the ionosphere-magnetosphere coupled system, it is generally accepted 
that the ionosphere supplies most of the mass/momentum, while the magnetosphere 
supplies most of the energy.  In order to address this problem, we use a 
time-dependent generalized polar wind model that consists of a fluid-based 
component at low altitudes and a macroscopic particle-in-cell (mac-PIC) 
component at high altitudes.  The simulation follows a magnetic flux tube that 
extends from ~100 km to 8 RE altitudes as it drifts across the cusp, polar cap, 
auroral and subauroral regions.  We investigate the relative importance of the 
WPI and the energetic electrons (of magnetospheric origin) on the ion outflow 
and temperature in the different high-latitude regions.  The main conclusions of 
this study are as follows:  (1) The interplay between the thermal ionospheric 
and energetic magnetospheric electrons produces a double-layer whose strength 
and altitude varies with time in response to the variation of th!
e geophysical conditions; (2) The WPI influence is more pronounced on the ion 
temperature and progressively less important on the vertical drift, u(H+), and 
the density, n(H+), respectively;  (3) The effects of the WPI are strongest in 
the cusp region; (4) In contrast, the presence of the magnetospheric electrons 
is the dominant factor for the evolutions of n(H+) and u(H+) in the polar cap;  
and (5) The profiles of n(H+) and u(H+) change more rapidly as they move from 
the subauroral to cusp region than as they move from the cusp to the polar cap.

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Discipline Category: Ionosphere