Plasma Transport from The Solar Wind to the Magnetosphere
ROSES ID: NNH05ZDA001N Selection Year: 2006
Program Element: Focused Science Topic
Principal Investigator: John Lyon
Affiliation(s): Dartmouth College
Project Member(s):
Rogers, Barrett Co-I Dartmouth College
Summary:
The mechanism by which the solar wind plasma enters the
magnetosphere remains an important and to a large degree
unanswered question. A number of mechanisms have been
proposed for this process. For example, there is direct
entry along newly reconnected field lines, there is
diffusive entry (perhaps drift mediated) along the
magnetopause, there is impulsive penetration, to name a
few. What does seem clear is that the amount of plasma
within the magnetosphere is correlated with the density in
the solar wind. This question of plasma entry has been
called out in the current NRA as an important science
question of interest to the NASA Sun-Earth Connection
Program.
We will attempt to determine the processes by which entry,
energization and energy extraction take place through a
number simulation codes, used singly and in concert. The
simulation codes are: 1. A global MHD magnetospheric code
which has been used successfully to model many of the
aspects of magnetospheric structure and dynamics. This will
be the workhorse for this project. It can be used to track
fluid elements from, say, positions in the plasma sheet to
their origins in the solar wind. 2. A particle tracking
code that integrates the Lorentz orbits of particles within
the system. In conjunction with the fields from the global
MHD code, it can give ihe currentsnformation about the
actual trajectories of the particles making up the
collisionless plasma. 3. Two fluid and hybrid codes to model
the boundary layers (magnetopause) of the global system. One
of the deficiencies of the MHD codes is that the boundary
layers are both not resolved and deficient in physics. This
makes the results of tracing particle trajectories through
such layers problematic.
Our approach will be two-fold. On one track we will
use the global MHD model to set up idealized situations
where the plasma enetry can be studied using the full array
of tools listed above. Typically, then the MHD code would
provide a base time-dependent configuration of electric and
magnetic fields, as well as fluid flows. The results for
plasma entry for the fluid model will then be compared
against the results for the particle tracing. The kinetic
codes will be used in conjunction with the particle tracing
to develop ideas about the actual rates of particle
penetration and reflection and energy gain or loss through
the boundary layer.
In the second track, we will try to
validate the models by reference to actual data. This is
generally easier with the MHD models than with the other
simulations. Here we will rely on a combination of single
event studies and upon statistical studies.
Publications:
Performance Year | Reference | Investigation Type | Actions |
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1 | Pulkkinen, T. I.; Goodrich, C. C.; Lyon, J. G.; (200...
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Presentations:
Performance Year | Reference | Actions |
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1 | Damiano, P. A.; Lotko, W.; Wiltberger, M. J.; Lyon,Â...
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1 | Damiano, P. A.; Lotko, W.; Wiltberger, M. J.; Lyon,Â...
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1 | Damiano, P. A.; Lotko, W.; Brambles, O. J.; Wiltberg...
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