CHARGED DUST ODYSSEYS       23 April 2007, 11am

Amara L. Graps

Institute of Physics of Interplanetary Space, Rome
and
Planetary Science Institute, Tucson

Amara.Graps@ifsi-roma.inaf.it


Charged Dust:
1. Intrinsic property of matter that occurs in two forms:
positive or negative, dependent on the deficiency or surplus
of electrons carried by fine particles of matter
2. Obligated Trash
3. Loaded Confusion
4. Excited Lint

Odyssey:
1.  An extended adventurous voyage or trip.
2.  An intellectual quest


ABSTRACT

The charging of cosmic dust as a topic of study provides nonintuitive
details of the important charge parameter in the electrodynamics
force, which plays a dominant role over the gravitational force for
the Universe's tiny cosmic dust particles. Cosmic dust particles are
rarely electrically neutral because they are immersed in space
plasmas, collecting ions, electrons, residual high-energy particles,
and receiving ultraviolet radiation from nearby stars. The tiny
particles electrically and dynamically respond to their environment
with surface charge potentials which closely follow the surrounding
plasma and magnetic field conditions. At the same time that the
particle charges up, it is responding to its environment dynamically
via the Lorentz electromagnetic force. Therefore, small cosmic dust
particles are ideal tracers of their astrophysical environments.

A variety of charged cosmic dust populations exist within the
magnetospheres of the planets in our solar system. The variable
charging of the small dust particles leads to the particles'
nonintuitive circumplanetary trajectories. One of the most dramatic
examples of the charging of cosmic dust is the Jovian dust streams:
high-speed (at least 200 km/sec) collimated streams of submicron-sized
particles traveling in the same direction from a source (Io) in the
Jovian system. Saturn, with a different source and a different plasma
environment joins Jupiter with a similar dust stream phenomena. The
Earth's dust and spacecraft debris yields yet another class of charged
particles. With time permitting, I will show these examples of the
charging effects on dust particles' dynamics in the magnetospheres of
the Earth, Jupiter and Saturn.