相关论文: Subsonic Mechanical Alignment of Irregular Grains
Dust grains emit intrinsic polarized emission if they are elongated and aligned in the same direction. The direction of the grain alignment is determined by external forces, such as magnetic fields, radiation, and gas flow against the dust…
The alignment of interstellar dust grains with magnetic fields provides a key method for measuring the strength and morphology of the fields. In turn, this provides a means to study the role of magnetic fields from diffuse gas to dense…
Earlier studies of grain alignment dealt mostly with interstellar grains that have strong internal relaxation of energy which aligns grain axis of maximum moment of inertia with respect to grain's angular momentum. In this paper, we study…
The radiative torque (RAT) mechanism is the most promising way of explaining observed polarization arising from aligned grains. We explore the efficiency of the grain alignment by an anisotropic radiation flow for an extensive ensemble of…
Interstellar medium is turbulent and this induces relative motions of dust grains. We calculate relative velocities of charged grains in a partially ionized magnetized gas. We account for anisotropy of magnetohydrodynamic (MHD) turbulence,…
Most astrophysical fluids are turbulent and magnetized. Fluctuations of polarization provide a promising way to study astrophysical magnetic turbulence. We discuss polarization that arises from grains and atoms aligned in respect to…
A quantitative analysis of grain alignment in the filamentary dark cloud L1755 in Ophiuchus is presented. We show, that the observed decrease of the polarization to extinction ratio for the inner parts of this quiescent dark cloud can be…
We consider a model of the dynamics of a magnetic grain, incorporating interactions with nuclear and paramagnetic spins, conduction electrons, and phonons. Decoherence comes both from the spins and the electrons, although electron effects…
Motivated by a recent study by Lazarian and Draine, which showed that a high degree of grain alignment of the paramagnetic dust is achievable if the rates of internal relaxation are controlled by the Barnett relaxation process, we undertake…
A detailed study of interstellar polarization efficiency toward molecular clouds is used to attempt discrimination between grain alignment mechanisms in dense regions of the ISM. Background field stars are used to probe polarization…
Multiscale phenomena which include several processes occuring simultaneously at different length scales and exchanging energy with each other, are widespread in magnetism. These phenomena often govern the magnetization reversal dynamics,…
Polarization of optical starlight and far-infrared thermal dust emission due to alignment of interstellar grains offers a powerful window to study magnetic fields in the various astrophysical environments, from the diffuse interstellar…
Grain alignment by radiative torques (RATs) has been extensively studied for various environment conditions, including interstellar medium, dense molecular clouds, and accretion disks, thanks to significant progress in observational,…
Interstellar dust grains are non-spherical and, in some environments, partially aligned along the direction of the interstellar magnetic field. Numerous alignment theories have been proposed, all of which examine the grain rotational…
We measure stability of two-dimensional granular mixtures in a rotating drum and relate grain configurations to stability. For our system, the smaller but smoother grains cluster near the center of the drum, while the larger, rougher grains…
The radiative torque (RAT) alignment of interstellar grains with ordinary paramagnetic susceptibilities has been supported by earlier studies. The alignment of such grains depends on the so-called RAT parameter $q^{\max}$ that is determined…
We reveal a deep connection between alignment of dust grains by RAdiative torques (RATs) and MEchanical Torques (METs) and rotational disruption of grains introduced by Hoang et al. (2019). The disruption of grains happens if they have…
The quantization of energy levels in very nanoparticles suppresses dissipative processes that convert grain rotational kinetic energy into heat. For grains small enough to have GHz rotation rates, the suppression of dissipation can be…
We discuss a new technique of studying magnetic fields in diffuse astrophysical media, e.g. interstellar and intergalactic gas/plasma. This technique is based on the angular momentum alignment of atoms and ions in their ground or metastable…
Extracting the grain size from the microscopic images is a rigorous task involving much human expertise and manual effort. While calculating the grain size, we will be utilizing a finite number of particles which may lead to an uncertainty…