CHARGING OF AGGREGATE GRAINS IN ASTROPHYSICAL ENVIRONMENTS

The charging of dust grains in astrophysical environments has been investigated with the assumption that these grains are homogeneous spheres. However, there is evidence which suggests that many grains in astrophysical environments are irregularly shaped aggregates. Recent studies have shown that ag...

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Bibliographic Details
Published inThe Astrophysical journal Vol. 763; no. 2; pp. 1 - 9
Main Authors Ma, Qianyu, Matthews, Lorin S, Land, Victor, Hyde, Truell W
Format Journal Article
LanguageEnglish
Published United States 01.02.2013
Subjects
Aggregates
ASTROPHYSICS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Charge
Charging
DUSTS
Dynamic structural analysis
ELECTRIC CURRENTS
ELECTRON EMISSION
EQUILIBRIUM
Evolution
Grains
MASS
NANOSTRUCTURES
PARTICLES
PHOTOEMISSION
PLANETS
PLASMA
Plasma currents
SATELLITES
SPHERICAL CONFIGURATION
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Summary:The charging of dust grains in astrophysical environments has been investigated with the assumption that these grains are homogeneous spheres. However, there is evidence which suggests that many grains in astrophysical environments are irregularly shaped aggregates. Recent studies have shown that aggregates acquire higher charge-to-mass ratios due to their complex structures, which in turn may alter their subsequent dynamics and evolution. In this paper, the charging of aggregates is examined including secondary electron emission and photoemission in addition to primary plasma currents. The results show that the equilibrium charge on aggregates can differ markedly from spherical grains with the same mass, but that the charge can be estimated for a given environment based on structural characteristics of the grain. The "small particle effect" due to secondary electron emission is also important for de terming the charge of micron-sized aggregates consisting of nano-sized particles.
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ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/763/2/77