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Laboratory Experiments on Rotation of Micron Size Cosmic Dust Grains with RadiationThe processes and mechanisms involved in the rotation and alignment of interstellar dust grains have been of great interest in astrophysics ever since the surprising discovery of the polarization of starlight more than half a century ago. Numerous theories, detailed mathematical models and numerical studies of grain rotation and alignment along the Galactic magnetic field have been presented in the literature. In particular, the subject of grain rotation and alignment by radiative torques has been shown to be of particular interest in recent years. However, despite many investigations, a satisfactory theoretical understanding of the processes involved in grain rotation and alignment has not been achieved. As there appears to be no experimental data available on this subject, we have carried out some unique experiments to illuminate the processes involved in rotation of dust grains in the interstellar medium. In this paper we present the results of some preliminary laboratory experiments on the rotation of individual micron/submicron size nonspherical dust grains levitated in an electrodynamic balance evacuated to pressures of approx. 10(exp -3) to 10(exp -5) torr. The particles are illuminated by laser light at 5320 A, and the grain rotation rates are obtained by analyzing the low frequency (approx. 0-100 kHz) signal of the scattered light detected by a photodiode detector. The rotation rates are compared with simple theoretical models to retrieve some basic rotational parameters. The results are examined in the light of the current theories of alignment.
Document ID
20040086480
Document Type
Conference Paper
Authors
Abbas, M. M. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Craven, P. D. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Spann, J. F. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Tankosic, D. (Alabama Univ. Huntsville, AL, United States)
LeClair, A. (Alabama Univ. Huntsville, AL, United States)
Gallagher, D. L. (NASA Marshall Space Flight Center Huntsville, AL, United States)
West, E. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Weingartner, J. (George Mason Univ. Fairfax, VA, United States)
Witherow, W. K. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Astrophysics
Meeting Information
35th COSPAR Scientific Assembly(Paris)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.