Theory and Hybrid Simulations of Transport due to Kinetic Alfven Waves at the Magnetopause
ROSES ID: NNH05ZDA001N Selection Year: 2006
Program Element: Focused Science Topic
Principal Investigator: Jay Johnson
Affiliation(s): Princeton University
Project Member(s):
Wing, Simon Collaborator The Johns Hopkins University
Lin, Yu Co-I Auburn University
Summary:
Recent observations have placed observational constraints on plasma
entry mechanisms for northward IMF conditions when the plasma sheet
cools and densifies. In particular, both in situ and remote
observations have found dawn-dusk asymmetries in the density and
temperature of the ion populations, and in situ particle distributions
show perpendicular ion heating of low energy ions on the dawnside
associated with strong compressional wave activity in the
magnetosheath. It is the purpose of this proposal to examine
transport processes that would occur due to kinetic and nonlinear
interactions associated with the large amplitude, low frequency waves
that are nearly always observed near the magnetopause in the context
of these observational constraints. We would address the following
scientific questions: (a) What is the nature of the low frequency wave
activity and how does it regulate plasma entry into the magnetosphere,
(b) What are the observational signatures expected from these
transport processes?, and (c) How do the observational signatures
compare with simulation and theory?
We will use a combined theoretical and computational approach to
understand how kinetic Alfven waves develop near the magnetopause and
contribute to transport. We will obtain wave solutions near the
magnetopause using the kinetic-fluid model (that include finite Larmor
radius effects and wave particle interactions) that we will use to
understand transport and heating at the magnetopause using methods of
nonlinear dynamics. We will compare these results with hybrid
simulations in a simplified slab geometry to understand the nonlinear
aspects of low-frequency MHD waves at the magnetopause. Using this
insight, we will perform and interpret three-dimensional hybrid
simulations in a realistic magnetospheric geometry. We will examine
the dependence of transport on solar wind conditions and the location
along the magnetopause where particle entry occurs. We will compare
our theoretical models with observations of wave activity, particle distributions,
and global asymmetries.
This project is directly relevant to the Living with a Star Targeted
Research and Technology program Focused Science Topic area (c) Solar
Wind Plasma Entry and Transport in the magnetosphere because we will
address the means by which plasma crosses the magnetopause and we will
quantify the amount of solar wind entering the magnetosphere due to
low frequency kinetic Alfven wave activity and
identify where it enters along the boundary. This proposal is also
relevant to NASA's national research objectives to explore the dynamic
earth system because we will have improved understanding of space
environmental conditions and their causes which will increase
capabilities for space flight and exploration.
Publications:
Performance Year | Reference | Investigation Type | Actions |
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1 | Lin, Y.; Johnson, J. R.; Wang, X. Y.; (2010), HybridÂ...
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Presentations:
Performance Year | Reference | Actions |
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1 | Johnson, J. R.; Lin, Y.; (2007), Signatures of Resonant ...
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1 | Lin, Y.; Johnson, J. R.; Wang, X.; (2007), Hybrid Sim...
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1 | Johnson, J. R.; Lin, Y.; Wing, S.; Kim, E.; (2008), ...
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1 | Johnson, J.; Otto, A.; Lin, Y.; Wing, S.; Kim, E.; ...
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1 | Lin, Y.; Johnson, J.; Wang, X.; (2009), Hybrid Simulat...
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