| Abstract |
Dust is a ubiquitous constituent of the interstellar medium, molecular
clouds, and circumstellar and protoplanetary disks. Dust emission
interferes with observations of cosmic microwave background (CMB)
temperature anisotropy and its polarized emission dominates the CMB
B-mode polarization that prevents us from getting insight into the
inflation epoch of the early universe. We study fundamental physical
processes of dust dynamics in plasma and explore their implications to
observations of the CMB, studies of magnetic fields, and formation of
planets. We quantified spinning dust emission (SDE) from wobbling small
grains with non-spherical shapes. We investigated the effects of
transient heating by UV photon and compressible turbulence on SDE. This
improved SDE model reproduces very well observation data by Wilkinson
Microwave Anisotropy Probe and allows a reliable subtraction of Galactic
contamination from the CMB. We identified grain helicity as the major
driver for grain alignment via radiative torques (RATs) and suggested an
analytical model of RATs based on this concept. Dust polarization
predicted by the model has been confirmed by numerous observations, and
can be used as a frequency template for the CMB B-mode searches. We
proposed a new type of dust acceleration due to magnetohydrodynamic
turbulence through transit time damping for large grains and quantified
a novel acceleration mechanism induced by charge fluctuations for very
small grains using Monte Carlo simulations. Grain velocities from these
new acceleration mechanisms are necessary for understanding dust
coagulation in protoplanetary disks and formations of planets. |