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We derive expressions for the photophoretic force on opaque spherical particles in a dilute gas in the optically thick regime where the radiation field is in local thermal equilibrium. Under those conditions, the radiation field has a…
Photophoresis is a physical process that transports particles in optical thin parts of protoplanetary disks, especially at the inner edge and at the optically surface. To model the transport and resulting effects in detail, it is necessary…
Photophoretic motion can transport illuminated particles in protoplanetary disks. In a previous paper we focused on the modeling of steady state photophoretic forces based on the compositions derived from tomography and heat transfer. Here,…
Photophoresis is a physical process based on momentum exchange between an illuminated dust particle and its gaseous environment. Its net effect in protoplanetary discs (PPD) is the outward transport of solid bodies from hot to cold regions.…
It is widely accepted that rocky planets form in the inner regions of protoplanetary disks (PPD) about 1 - 10 AU from the star. However, theoretical calculations show that when particles reach the size for which the radial migration is the…
We study dust accumulation by photophoresis in optically thin gas disks. Using formulae of the photophoretic force that are applicable for the free molecular regime and for the slip-flow regime, we calculate dust accumulation distances as a…
In a set of 16 drop tower experiments the motion of sub-mm to mm-sized particles under microgravity was observed. Illumination by a halogen lamp induced acceleration of the particles due to photophoresis. Photophoresis on dust-free…
Protoplanetary disks start their lives with a dust free inner region where the temperatures are higher than the sublimation temperature of solids. As the star illuminates the innermost particles, which are immersed in gas at the sublimation…
In protoplanetary disks, the differential gravity-driven settling of dust grains with respect to gas and with respect to grains of varying sizes determines the observability of grains, and sets the conditions for grain growth and eventually…
Aerosol particles experience significant photophoretic forces at low pressure. Previous work assumed the average particle temperature to be very close to the gas temperature. This might not always be the case. If the particle temperature or…
Although known for almost a century, the photophoretic force has only recently been considered in astrophysical context for the first time. In our work, we have examined the effect of photophoresis, acting together with stellar gravity,…
Light pressure effect has been discovered long ago and has been used as an optical method to manipulate microand nanoparticles. It is usually considered as a nonresonant effect determined by the transfer of the momentum of light. However,…
Photothermal effects have been pointed out as prominent sources of forces in optomechanical systems, competing with the standard radiation pressure interactions. In this Article, we derive a novel and accurate model for the prediction of…
Recent multi-wavelength observations suggest that inner parts of protoplanetary disks (PPDs) have shorter lifetimes for heavier host stars. Since PPDs around high-mass stars are irradiated by strong ultra-violet radiation, photoevaporation…
Photophoretic force due to the optically-induced thermal effect provides an effective way to manipulate the light-absorbing particles suspended in ambient gases. However, how this force temporally responds to the intensity modulation of the…
We explore dust flow in the hottest parts of protoplanetary discs using the forces of gravity, gas drag and radiation pressure. Our main focus is on the optically thin regions of dusty disc, where the dust is exposed to the most extreme…
In a laboratory experiment, water-ice aggregates are trapped in a vacuum chamber at a pressure of 2 mbar due to photophoresis and thermophoresis. The particles are located between a Peltier element at the bottom at 250 K and a reservoir of…
We consider the mechanism of photophoretic transport in protoplanetary disks that are optically thick to radiation. Here, photophoresis is not caused by the central star but by temperature fluctuations that subject suspended solid…
Scaling down miniature rotorcraft and flapping-wing flyers to sub-centimeter dimensions is challenging due to complex electronics requirements, manufacturing limitations, and the increase in viscous damping at low Reynolds numbers.…
Photoevaporation is an important dispersal mechanism for protoplanetary disks. We conduct hydrodynamic simulations coupled with ray-tracing radiative transfer and consistent thermochemistry to study photoevaporative winds driven by…