[ExI] first step as principle investigator

[Amara Graps]

Hi Extropes,

The nine months I spent last year writing government grant proposals
wasn't for nothing, this morning I learned that my last NASA proposal
will be funded (a small project: 4 months per year for two years). This
is my first research proposal where I'm the 'principle investigator'.

This means that I'm part-way on the road now to being a self-funded
planetary astronomer. After making my large move to a 2 year salary
position, this funding source isn't necessary for my life now, but
it does give me a buffer while I gain more practice writing proposals
and submit several more like this one, so that I can be completely
self-funded when my current SwRI position ends.

I've pasted the topic below.

Amara

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The Development of the Saturnian Dust Streams

Interplanetary dust streams are highly collimated, high-velocity
submicron particles that can extend over several A.U. They arise from
the coupling of planetary magnetic fields and sources of dust production
in circumplanetary environments.  The first streams were detected
emanating from the Jupiter system by the Ulysses mission in 1992. They
were detected continually inside of Jupiter's magnetosphere and dozens
of times in interplanetary space by the Ulysses, Galileo and Cassini
spacecraft. Dust streams emanating from the Saturn system were detected
by the Cassini Cosmic Dust Analyser (CDA) in 2004, at a distance of half
an A.U., and they continue to be detected as Cassini orbits Saturn.
Graps \cite{Graps:2000a}\ identified Io as the dominant source of the
Jovian dust stream particles, but the source or sources of Saturnian
dust stream particles is unknown. Possibilities to be investigated
include (but are not limited to) Enceladus geysers, fragmented E~ring
particles, and collisional fragments from the Main rings. CDA includes a
time-of-flight mass spectrometer, providing compositional information
not available from Galileo and Ulysses, which will provide new insights
and constraints to address particle source issues.

The coupling of the planetary magnetic fields and their sources of dust
production has been found to have large physical consequences in the
Jovian and Saturnian magnetospheres. Given the prodigious quantity of
dust produced, Graps \cite{Graps:2006a}\ and others \cite{Wahl:2006}\
have indicated that dust production in both the Jupiter and Saturn
systems may be large enough that conditions would exist for dusty
plasmas, which lead to collective behavior of the dust particles. This
can be a factor in the formation of dust streams. This coupling of the
planetary magnetic fields and their sources of dust production also
leaves its imprint on the dust streams' signature in frequency space,
allowing one to study the source of the dust streams.

Not all dust destined to escape in streams from a circumplanetary region
escape immediately. The time for a particle to charge up and accelerate
gives a residential lifetime to the smallest particles in the vicinity
of their host. Such a temporary residence of a population of tiny
particles can be a hazard to objects in the vicinity (instruments,
people), as well as a source dust population for other physical
processes (e.g., impact related). Once these particles escape into
streams into interplanetary space, they have been correlated with the
leading edges of high-speed solar wind streams (called corotating
interaction regions or CIRs) and the Sun's coronal mass ejections
(CMEs), adding further to the complexity of their dynamical evolution.

We propose to quantify the conditions under which collimated dust
streams form and evolve in the Saturn system to reproduce the CDA
observations and compare it to the generation of dust streams in the
Jupiter system. Objectives include:

\begin{itemize}
\item Determine the sources of dust stream particles from the Saturn
system with frequency analysis and modeling and compare them to those of
Jovian dust stream particles. Can dust production required for streams
be generalized to other solar system bodies (e.g., geysers on Triton)?
\item Model the contribution of both planetary and solar magnetic fields
to the formation and evolution of dust streams.
\item Determine the time evolutionary state of the spatial density and
particle size distribution of stream particles within the Saturn
magnetosphere.
\item  Determine the locations and (plasma, dust) parameters of dusty
plasma conditions and their impact in the formation of dust streams.
\end{itemize}

The analysis of Cassini datasets with a focus on the Saturnian dust
streams is valuable for understanding the dust streams' source, for
understanding the dynamical development of the streams, and for
predicting where we might detect streams elsewhere, thereby  realizing
the objective of the Cassini Data Analysis Program (CDAP) of enhancing
the scientific return of the Cassini mission. This project supports
NASA's Strategic Goals by Strategic Sub-goal 3C, it contributes to the
NASA Science Outcomes 3B.1, as well as Science Outcomes 3B.3. As cosmic
dust is both a building block and by-product of solar system
evolutionary processes, this project also contributes to NASA's Science
Outcomes: 3C.1.

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Amara Graps, PhD      www.amara.com
Research Scientist, Southwest Research Institute (SwRI), Boulder, Colorado