Surface-induced near-field scaling in the Knudsen layer of a rarefied gas

Abstract

We report on experiments performed within the Knudsen boundary layer of a low-pressure gas. The non-invasive probe we use is a suspended nano-electro-mechanical string (NEMS), which interacts with ${}^4$He gas at cryogenic temperatures. When the pressure $P$ is decreased, a reduction of the damping force below molecular friction $\propto P$ had been first reported in Phys. Rev. Lett. Vol 113, 136101 (2014) and never reproduced since. We demonstrate that this effect is independent of geometry, but dependent on temperature. Within the framework of kinetic theory, this reduction is interpreted as a rarefaction phenomenon, carried through the boundary layer by a deviation from the usual Maxwell-Boltzmann equilibrium distribution induced by surface scattering. Adsorbed atoms are shown to play a key role in the process, which explains why room temperature data fail to reproduce it.

arXiv commentArticle plus supplementary material

References in corpus (6)

• High frequency nano-optomechanical disk resonators in liquids
• Generalized Knudsen Number for Unsteady Fluid Flow
• Nanofluidics of Single-crystal Diamond Nanomechanical Resonators
• Slippage and boundary layer probed in an almost-ideal gas by a nano-mechanical oscillator
• Large variation in the boundary-condition slippage for a rarefied gas flowing between two surfaces
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Cited by in corpus (2)

• Fully suspended nano-beams for quantum fluids
• Precision Measurement of Sub-Continuum Gas Conduction within Micro-Confinements