Open AccessRadiation pressure measurements on micron‐size individual dust grains
Author(s) -
Abbas M. M.,
Craven P. D.,
Spann J. F.,
Witherow W. K.,
West E. A.,
Gallagher D. L.,
Adrian M. L.,
Fishman G. J.,
Tankosic D.,
LeClair A.,
Sheldon R.,
Thomas E.
Publication year - 2003
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002ja009744
Subject(s) - radiation pressure , radiation , scattering , particle radiation , optics , extinction (optical mineralogy) , materials science , mie scattering , particle (ecology) , range (aeronautics) , electromagnetic radiation , atomic physics , refractive index , torr , beam (structure) , physics , charged particle , light scattering , ion , oceanography , composite material , quantum mechanics , thermodynamics , geology
Measurements of electromagnetic radiation pressure have been made on individual silica (SiO 2 ) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2‐ to 6.82‐μm range and irradiating them from above with laser radiation focused to beam widths of ∼175–400 μm at ambient pressures ∼10 −3 –10 −4 torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least‐squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO 2 and the corresponding extinction and scattering efficiencies.