Abstract
Abstract. We present in situ measurements of small-scale fluctuations in aerosol populations as recorded through a mesospheric cloud system from the Faraday cups DUSTY and MUDD during on the MAXIDUSTY-1 and 1B sounding rocket payloads launched in the summer of 2016. Two mechanically identical DUSTY probes mounted with an inter-spacing of ∼10 cm recorded very different currents, with strong spin modulation, in certain regions of the cloud system. A comparison to auxiliary measurement show similar tendencies in the MUDD data. Fluctuations in the electron density are found to be generally anti-correlated to the negative aerosol charge density on all length scales; however, in certain smaller regions the correlation turns positive. We have also compared the spectral properties of the dust fluctuations, as extracted by wavelet analysis, to polar mesospheric summer echo (PMSE) strength. In this analysis, we find a relatively good agreement between the power spectral density (PSD) at the radar Bragg scale inside the cloud system; however the PMSE edge is not well represented by the PSD. A comparison of proxies for PMSE strength, constructed from a combination of derived dusty plasma parameters, shows that no simple proxy can reproduce PMSE strength well throughout the cloud system. Edge effects are especially poorly represented by the proxies addressed here.
Highlights
The terrestrial mesosphere, situated at ∼ 50–100 km, contains the ambient prerequisites to house a number of different types of nanoparticles
In this work we present the measurements from the MAXIDUSTY campaign, with special emphasis on the MAXIDUSTY-1B payload launched from Andøya Space Center, 8 July 2016
For comparison to DUSTY, we look at the currents from the MUltiple Dust Detector (MUDD)-1 and MUDD-3 probes since these had observation modes with attracting potentials to ensure that even the smallest impact fragments were measured
Summary
The terrestrial mesosphere, situated at ∼ 50–100 km, contains the ambient prerequisites to house a number of different types of nanoparticles. From sub-nanometre sized meteoric smoke particles (MSPs) coagulated from ablation vapours of meteors to ice particles with radii of several tens of nanometres, aerosols in this region vary greatly in composition and size. Such variation makes mesospheric ice and dust particles important in many physical and chemical processes in the atmosphere. Sub-visual particles can produce coherent radar echoes at frequencies between some tens of megahertz and ∼ 1 GHz, by reducing the electron diffusivity such that gradients in electron density can persist for long time periods and produce radar backscatter at the radar Bragg scales Such echoes are called polar mesospheric summer echoes Such echoes are called polar mesospheric summer echoes (PMSEs: see e.g. Rapp and Lübken, 2004; mesospheric ice: see e.g. Rapp and Thomas, 2006, for comprehensive reviews)
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