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Space Plasma Physics and Planetary Science
|From a broad perspective my interest
in understanding plasma acceleration processes and magnetic field
modifications in planetary magnetospheres. I am also interested in
bridging the gap between magnetospheric and atmospheric sciences by
incorporating elastic and inelastic interactions between charged and
neutral particles and tracking the mass, energy and momentum feedback
between the neutral and ionized populations. This feedback is also
tracked via the local influence on the electric and magnetic fields.
the Cassini spacecraft discovered a
plume of water-ice particles, vapor, and dust grains jetting outward
from the southern polar region of Saturn’s moon Enceladus.
Perturbations in the velocity and magnetic field of the incident flow
seen over an extended region are evidence of mass loading of
Saturn’s magnetosphere by ions likely produced via charge
exchange in the expanding neutral plume. For this project I have been
incorporating neutral fluid components into an existing 3D multi-fluid
modeling infrastructure to investigate the interaction between the
plume material and the ambient magnetospheric plasma. The ion and
neutral fluids interact through charge exchange, and the production and
loss of ions and neutrals is monitored through source and loss terms in
each fluid species in each grid cell. The model is in the process of
against the Cassini spacecraft observations of magnetic field and
plasma velocity perturbations and used in conjunction with the CAPS ion
energy distributions to determine the importance of ion-neutral
interactions for transport of mass and energy near Enceladus. Much of
the data analysis work on the project is done in collaboration with the
Cassini CAPS team, which is an exciting and dynamic group involved
directly with instrument and new science coming out of the most recent
observations. Prospective students interested in an Enceladus orSaturn related research project should feel free to contact me.
There are currently 2 Mars projects that I am currently involved in,
the first involves studying Mars atmospheric electrodynamics using a
combination of spacecraft observations and simulations. This is truly
the testbed for developing the neutral atmosphere coupling to the space
plasma environment. Mars provides us with a natural laboratory to study
these interactions due the diffuse atmosphere and exosphere and lack of
a strong internal magnetic moment. Without a large magnetosphere, a
significant fraction of charged particles from the solar wind can
interact with the Mars' upper atmosphere creating a region of direct
coupling between the magnetized solar wind and the neutral atmosphere.
This work is performed in conjunction with several members of the SSL
at UC Berkeley who are working on the atmospheric models as well as
data analysis for ground-truthing the newly developed coupled models.
This project is just getting started, so motivated and interested
students should feel free to contact me about research opportunities
related to this work. The second project is an ongoing collaboration
with C. Johnson at UBC
and K. Lawrence at Stanford, which involves examining Mars'
atmosphere and the various loss mechanisms responsible for its
evolution to the current day state.
Previous and Continuing
Ganymede & other Galilean Moons
This project takes us to
the Jovian system where recent UV auroral observations of Ganymede and
Jupiter have demonstrated that our current understanding of plasma
acceleration mechanisms in the magnetosphere (expressed as aurora) is
approach taken to study this system involves using three-dimensional
multi-fluid simulations developed by R. Winglee which allow
for several different ion species to interact in the system as well as
incorporate the ion cyclotron
effects into both the momentum and electric field equations. This
powerful tool enables us to study differential heating and acceleration
between various ion species sourced from both the incident Jovian
magnetospheric plasma and Ganymede's own ionosphere. Using 3D imaging
software significant insight has been gained pertaining to the location
and morphology of critical boundary layers in Ganymede's magnetosphere,
and over several years I developed a suite of diagnostic tools
for better comparison/integration with a range of observational data
gathered by instruments on the Galileo spacecraft,
Voyager spacecrafts, and Hubble Space Telescope's STIS. This
integrated approach yields a more physically accurate and
sophisticated picture of how Ganymede and its
magnetosphere are modifying Jupiter's magnetosphere and how the plasma
is affected within this perturbed region.
I am very much intersted in taking some of the new modeling techniques
developed for Enceladus which incorporate ion neutral interactions and
applying them to the Jovian satellites, expecially for Io. Prospective
students with interests in conducting studies of any of the Jovian
satellites should feel free to contact me about potential projects in
this area. With the upcoming Juno mission and potentially a future
flagship mission to the Jovian system, these topics are seeing some
renewed intersted and enthusiam across the community.
Along with understanding the interactions between
Jupiter and Ganymede local to Ganymede's near space environment, I
initially worked on some early research pertaining to the study of the Jovian system from a
I presented some preliminary results from the Jovian global simulation
the Magnetospheres of Outer Planets conference in the summer of 2002
and findings on ionospheric outflow rates and Io torus stability were
shown at the Fall 2002 AGU. Undergraduate researcher Laurel
Rachemeler, now in graduate school at UC Boulder, continued the Jupiter
research studying the break-down of corotation and magnetic field
warping. Recent developments were presented at
the Fall 2004 AGU by our undergraduate researcher Angela Stickle, now in graduate school at Brown University.
Research from days of old...
Low Frequency Nuclear Magnetic Resonance(NMR)
study of Nuclear Spin Relaxation in 2-tertiarybutyl 4-methyl
hydroxybenzene. Senior thesis, Bryn
, Adviser Peter Beckmann (paper published 2004!
The Stability of Liquid Water in Porous Rocks in a
from ASGSB Meeting 2000. NASA Astrobiology Academy, Ames Research Center,
Characterization of Light Emitting Diodes for Plant
Growth: Power efficiencies for LEDs in bioregenerative life support
from ASGSB Meeting 2001. Space Life Sciences Training Program, Kennedy Spaceflight
P.I. James Scott Young