Earth Planets Space, Vol. 65 (No. 3), pp. 157-165, 2013
Jonathan D. Kerby1, R. Terik Daly1,2, and Daniel E. Austin1
1Department of Chemistry and Biochemistry, Brigham
Young University, Provo, Utah, U.S.A.
2Department of Geological Sciences, Brigham Young University, Provo, Utah, U.S.A.
(Received November 7, 2011; Revised July 29, 2012; Accepted August 20, 2012; Online published March 12, 2013)
In situ cosmic dust analyzers, like those aboard
Cassini, Galileo, and Stardust, provide important data about cosmic
dust, including the chemical composition of dust particles.
Correctly interpreting the data from these cosmic dust analyzers
requires laboratory calibration experiments. By studying the impact
mass spectrum from a particle of known composition, an unknown
particle's composition can be inferred from its impact mass
spectrum measured in situ. This work expands a recently
presented method, electrospray charging, introduced as a means of
charging minerals, astrophysical ices, and mineral-ice mixtures
that are not electrically conductive. This overcomes a limitation
of current dust accelerators: they can only charge, and therefore
accelerate, electrically conductive particles. This paper presents
experiments demonstrating that microparticles (typically 2
micrometers) of olivine, a common mineral in meteorites, and of an
ordinary chondrite (Allan Hills A 79045) can be electrically charged even though neither
is electrically conductive. This article discusses the acceleration
potential of electrospray-charged projectiles, and explores ways to
overcome the challenges implicit in coupling an electrospray source
to a dust accelerator. Electrospray charging may enable experiments
with novel projectiles that are better analogues for cosmic dust
than the conductive projectiles currently in use. Theoretical
charging limits using this technique would allow micron-sized
particles to be accelerated to several km/s using 3 MV potential,
with higher velocities for smaller particles.
Key words: Cosmic dust, dust accelerator, olivine, chondrite, microparticle impact, cosmic dust analyzer.