Electric dipole moments and disalignment of interstellar dust grains

Abstract

The degree to which interstellar grains align with respect to the interstellar magnetic field depends on disaligning as well as aligning mechanisms. For decades, it was assumed that disalignment was due primarily to the random angular impulses a grain receives when colliding with gas-phase atoms. Recently, a new disalignment mechanism has been considered, which may be very potent for a grain that has a time-varying electric dipole moment and drifts across the magnetic field. We provide quantitative estimates of the disalignment times for silicate grains with size > approximately 0.1 micron. These appear to be shorter than the time-scale for alignment by radiative torques, unless the grains contain superparamagnetic inclusions.

12 pages, 9 figures, submitted to MNRAS

References in corpus (11)

• The absence of crystalline silicates in the diffuse interstellar medium
• Radiative torques: Analytical Model and Basic Properties
• Tracing Magnetic Fields with Aligned Grains
• Radiative torque alignment: Essential Physical Processes
• Dust Dynamics in Compressible MHD Turbulence
• Magnetic Fields via Polarimetry: Progress of Grain Alignment Theory
• Radiative torques alignment in the presence of pinwheel torques
• Alignment of Dust with Magnetic Inclusions: Radiative Torques and Superparamagnetic Barnett and Nuclear Relaxation
• On the Crystallinity of Silicate Dust in the Interstellar Medium
• On the Disalignment of Interstellar Grains
• Thermal Flipping of Interstellar Grains

Cited by in corpus (5)

• Magnetic Properties of Dust Grains, Effect of Precession and Radiative Torque Alignment
• Paramagnetic alignment of small grains: a novel method for measuring interstellar magnetic fields
• Alignment and rotational disruption of dust
• Revisiting Acceleration of Charged Grains in Magnetohydrodynamic Turbulence
• Two modes of carbonaceous dust alignment