Laboratory Investigation Of The Effect Of Surface Roughness On Photoemission From Surfaces In Space

Abstract

Surfaces in space collect charges due to exposure of solar ultraviolet (UV) radiation, electrons, and ions. Throughout the solar system, UV-generated photoelectrons dominate the charging balance and exposed surfaces tend to charge positively. The surface potential of exposed objects depends on the material properties of their surfaces. Composition and particle size primarily affect the quantum efficiency of photoelectron generation; however, surface roughness can also control the charging process. Here we examine the role of surface roughness in generating photoelectrons in dedicated laboratory experiments using solid and dusty surfaces of the same composition. Using Langmuir probe measurements, we explore the measured plasma conditions above insulating surfaces exposed to UV, and we show that the photoemission current from a dusty surface is largely reduced due to its higher surface roughness, which causes a significant fraction of the emitted photoelectrons to be re-absorbed within the surface.

Publication Date

7-1-2018

Publication Title

Planetary and Space Science

Volume

156

Number of Pages

92-95

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.pss.2017.10.014

Socpus ID

85032934039 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85032934039

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