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Related papers: An adiabatic approximation for grain alignment the…

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We discuss the dynamics of dust grains subjected to uncompensated torques arising from H_2 formation. In particular, we discuss grain dynamics when a grain spins down and goes through a ``crossover''. As first pointed out by Spitzer &…

Astrophysics · Physics 2009-10-28 A. Lazarian , B. T. Draine

This work explores the manner in which classical phase space distribution functions converge to the microcanonical distribution. We first prove a theorem about the lack of convergence, then define a generalization of the coarse-graining…

Statistical Mechanics · Physics 2024-08-26 Casey O. Barkan

Interstellar dust grains exhibit complex dynamics which is essential for understanding many key interstellar processes that involve dust, including grain alignment, grain growth, grain shattering etc. Grain rotational and translational…

Astrophysics · Physics 2007-05-23 A. Lazarian , Huirong Yan

This paper establishes a quantitative, uniform-in-time diffusion approximation for the joint law of a broad class of fully coupled multiscale stochastic systems. We derive a precise characterization of the limiting joint distribution as a…

Probability · Mathematics 2026-04-02 Longjie Xie , Xicheng Zhang

In various applications one is interested in quantum dynamics at intermediate evolution times, for which the adiabatic approximation is inadequate. Here we develop a quasi-adiabatic approximation based on the WKB method, designed to work…

Quantum Physics · Physics 2017-07-28 Siddharth Muthukrishnan , Daniel A. Lidar

The supersaturation equation for a vertically moving adiabatic cloud parcel is analysed. The effects of turbulent updrafts are incorporated in the shape of a stochastic Lagrangian model, with spatial and time correlations expressed in terms…

Atmospheric and Oceanic Physics · Physics 2023-05-05 Manuel Santos Gutiérrez , Kalli Furtado

During the evolution of protoplanetary disks, dust grains start to grow, form larger particles, settle to the midplane, and rearrange the disk, mainly by the inward radial drift. Because of this, dust pebbles with an irregular shape usually…

Earth and Planetary Astrophysics · Physics 2025-11-05 Moritz Lietzow-Sinjen , Stefan Reissl , Mario Flock , Sebastian Wolf

We study the hydrodynamical behavior occurring in the turbulent interaction zone of a fast moving red supergiant star, where the circumstellar and interstellar material collide. In this wind-interstellar medium collision, the familiar bow…

Solar and Stellar Astrophysics · Physics 2011-05-31 Allard Jan van Marle , Zakaria Meliani , Rony Keppens , Leen Decin

Interstellar space hosts nanometre- to micron-sized dust grains. The carbonaceous-rich component of these grain populations emits in infrared bands, observed remotely for decades with telescopes and satellites. They are a key ingredient of…

Astrophysics of Galaxies · Physics 2020-05-20 Emmanuel Dartois , Emeline Charon , Cécile Engrand , Thomas Pino , Christophe Sandt

Inference-time alignment for diffusion models aims to adapt a pre-trained reference diffusion model toward a target distribution without retraining the reference score network, thereby preserving the generative capacity of the reference…

Machine Learning · Statistics 2026-02-05 Jinyuan Chang , Chenguang Duan , Yuling Jiao , Yi Xu , Jerry Zhijian Yang

We study the extinction properties of the composite dust grains, consisting of host silicate spheroids and graphite as inclusions, using discrete dipole approximation (DDA). We calculate the extinction cross sections of the composite grains…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nisha Katyal , Ranjan Gupta , D B Vaidya

We present the main aspects of the adiabatic theory and show that it can be used to study the motion of test particles in general relativity. The theory is based upon the use of vector elements of the orbits and adiabatic invariants. To…

The measures of mechanical alignment were obtained for both prolate and oblate grains when their temperature is comparable with grain kinetic energy devided by k, the Boltzmann constant. For such grains, the alignment of angular momentum,…

Astrophysics · Physics 2014-10-10 A. Lazarian

The problem of spin precession in a time-dependent magnetic field is considered in the adiabatic approximation where the field direction or the angular velocity of its rotation is changing slowly. The precession angles are given by…

Quantum Physics · Physics 2016-09-08 M. S. Marinov , Eugene Strahov

We develop a model of dust evolution in a multiphase, inhomogeneous ISM including dust growth and destruction processes. The physical conditions for grain evolution are taken from hydrodynamical simulations of giant molecular clouds in a…

Astrophysics of Galaxies · Physics 2016-11-09 Svitlana Zhukovska , Clare Dobbs , Edward B. Jenkins , Ralf Klessen

Barnett relaxation, first described by Purcell in 1979, appears to play a major role in the alignment of grains with the interstellar magnetic field. In 1999, Lazarian and Draine proposed that Barnett relaxation and its relative, nuclear…

Astrophysics of Galaxies · Physics 2017-08-16 Erald Kolasi , Joseph C. Weingartner

We introduce a deductive statistical mechanics approach for granular materials which is formally built from few realistic physical assumptions. The main finding is an universal behavior for the distribution of the density fluctuations. Such…

Soft Condensed Matter · Physics 2008-06-25 T. Aste , T. Di Matteo

Adiabatic invariants are introduced and shown to provide an approximate second integral of motion for the non-integrable Dicke model, in the energy region where the system exhibits a regular dynamics. This low-energy region is always…

We investigate shattering and coagulation of dust grains in turbulent interstellar medium (ISM). The typical velocity of dust grain as a function of grain size has been calculated for various ISM phases based on a theory of grain dynamics…

Astrophysics · Physics 2009-11-13 Hiroyuki Hirashita , Huirong Yan

We use the Fokker Planck equation as a starting point for studying the orientational probability distribution of an Active Brownian Particle (ABP) in $(d+1)$ dimensions. This Fokker Planck equation admits an exact solution in series form…

Statistical Mechanics · Physics 2020-08-26 Supurna Sinha