Rick Kohnert, Scott Robertson, and Scott Knappmiller with the two rocket payloads for noctilucent cloud particles.
Dusty plasma is plasma containing small particles
in suspension. In industry, dust is a contaminant
and this is a motivation for its removal from
semiconductor processing lines, smokestacks, and
diesel exhausts. In nature, the ionosphere
contains dust from the ablation of meteors,
planets have rings of dust that are charged by
solar wind particles trapped in their
magnetospheres, and objects without
magnetospheres (the Moon and Eros, for example)
have dusty surfaces that are charged by solar
wind particles and by photoelectric emission.
Our research on dusty plasmas has been motivated by
these naturally occurring plasmas. There are five
major areas to our research.
Noctilucent cloud in the summer polar mesosphere.
- The largest
research project is the development and launch of
rocket-borne probes to detect the dust in the
mesosphere from meteor ablation and the larger
noctilucent cloud particles that form in the
arctic summer when ice nucleates and grows on
- Dust is placed on surfaces
in laboratory plasma with UV illumination to find
the charge that accumulates. The charge can cause
the dust to stick harder to the surface or to be
lifted from it. The motivation is to understand
the dust hazard that is faced by instruments and
astronauts on the moon.
- "Smoky plasma" is
generated by evaporating and condensing metal
vapor and adding these nanoparticles to plasma.
These particles mimic the meteoritic particles in
the ionosphere and allow study of charge balance
in plasma when there are solid particles.
research makes extensive use of probe methods for
plasma and the data are used in developing models
for particle and energy balance. The improvement
of probe methods and plasma modeling is done in
parallel with the dusty plasma research.
- We are developing a mass analyzer (LAMA) for a
deep-space probe that will find the elemental
composition of impacting interplanetary and
interstellar dust. The impacts produce a puff of
plasma which is directed into a time-of-flight
mass analyzer. The data reveal which elements are
present and their isotopic ratios.