44,084 research outputs found
Acceleration of dust particles by low-frequency Alfv\'en waves
We investigate the efficiency of acceleration of charged dust particles by
low-frequency Alfv\'en waves in nonlinear approximation. We show that the
longitudinal acceleration of dust particles is proportional to the square of
the soliton amplitude , while the transversal acceleration is of
. In the conditions of the interstellar medium the resulting velocity
of dust particles can reach 0.3 to 1 km s.Comment: 8 pages, no figs, accepted in Phys. Lett.
Structure of Dusty Plasma under Microgravity
The structure of dust particles in dusty plasmas under microgravity has been analyzed by molecular dynamics simulation. The charge neutrality condition satisfied by the system composed of dust particles and ambient plasma is properly taken into account. It is shown that dust particles form shell structures at low temperatures and the number of shells are obtained as a phase diagram in the plane of two parameters characterizing the system: the number of particles and the strength of screening. It is also shown that these structures are almost independent of the strength of screening
Magneto-thermal condensation modes including the effects of charged dust particles
We study thermal instability in a magnetized and partially ionized plasma
with charged dust particles. Our linear analysis shows that the growth rate of
the unstable modes in the presence of dust particles strongly depends on the
ratio of the cooling rate and the modified dust-cyclotron frequency. If the
cooling rate is less than the modified dust-cyclotron frequency, then growth
rate of the condensation modes does not modify due to the existence of the
charged dust particles. But when the cooling rate is greater than (or
comparable to) the modified dust-cyclotron frequency, the growth rate of
unstable modes increases because of the dust particles. Also, wavenumber of the
perturbations corresponding to the maximum growth rate shifts to the smaller
values (larger wavelengths) as the cooling rate becomes larger than the
modified dust-cyclotron frequency. We show that growth rate of the condensation
modes increases with the electrical charge of the dust particles.Comment: accepted by MNRA
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Observations of Saharan dust layer electrification
Electrification of atmospheric dust influences the coagulation, wet removal and fall speeds of dust particles. Alignment of dust particles can also occur in fair weather atmospheric electrical conditions if the particles are charged. However, very few electrical measurements made in elevated dust layers exist. Balloon-borne charge and particle instrumentation have been used to investigate the electrical properties of elevated Saharan dust layers. Soundings from the Cape Verde Islands, which experience frequent Saharan dust outbreaks, intercepted several dust layers. Two balloon soundings during summer 2009 detected dust particles in layers up to 4 km altitude. Simultaneous electrical measurements showed charge inside the dust layers, with a maximum measured charge density of 25 pC m − 3, sufficient to influence wet removal processes
Onset of cavity deformation upon subsonic motion of a projectile in a fluid complex plasma
We study deformation of a cavity around a large projectile moving with
subsonic velocity in the cloud of small dust particles. To solve this problem,
we employ the Navier--Stokes equation for a compressible fluid with due regard
for friction between dust particles and atoms of neutral gas. The solutions
shows that due to friction, the pressure of dust cloud at the boundary of the
cavity behind the projectile can become negative, which entails formation of a
microscopic void free from dust particles -- the cavity deformation.
Corresponding threshold velocity is calculated, which is found to decrease with
increasing cavity size. Measurement of such velocity makes it possible to
estimate the static pressure inside the dust cloud.Comment: 7 pages, 3 figure
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