2014 Spring Physics Colloquium Series: Lorin Matthews, Ph.D.

DateFebruary 5, 2014
Time4:00 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Lorin Matthews, Ph.D.

Associate Professor, Department of Physics

Baylor University

Modeling the Photophoretic Force on Fractal Aggregates

Photophoresis is a force which can dominate the motion of illuminated dust particles in low
pressure environments of laboratory experiments, planetary atmospheres, or protoplanetary
disks. The force arises when gas incident upon the warmer, illuminated side rebounds from
the surface with a higher velocity than gas incident on the cooler, shaded side. The strength
of the photophoretic force depends on material properties like thermal conductivity,
accommodation coefficients and optical properties. Previous theoretical investigations of the photophoretic force assume spherical dust particles, but the dust in natural environments is
usually non-spherical and often an aggregate of smaller particles. This talk will present a
numerical simulation used to study the photophoretic force on fractal dust aggregates
consi4:00 p.m.sting of ým-sized spheres. And address the question of whether the resulting drift velocity is great enough to play a role in sorting materials in a protoplanetary disk, changing the compositions of planets formed from the dust.

For more information, please contact:
Dr. Anzhong Wang 254-710-2276

PublisherDepartment of Physics
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