In-situ Measurements of Mesospheric Aerosols - On the observable characteristics of nanoscale ice and meteoric smoke particles

• Published in: Review of Scientific Instruments
• Main Author: Antonsen, Tarjei
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UiT Norges arktiske universitet 2019
• Subjects: VDP::Matematikk og Naturvitenskap: 400::Fysikk: 430::Rom- og plasmafysikk: 437; VDP::Mathematics and natural science: 400::Physics: 430::Space and plasma physics: 437; Andøya; Faraday
• Online Access: https://hdl.handle.net/10037/14521

Two sounding rocket payloads were launched from Andøya Space Centre (69.29 N, 16.02 E) during the summer of 2016 within the MAXIDUSTY campaign. Their payloads contained instrumentation aimed at investigating the characteristics of nanoscale aerosols in the upper summer mesosphere, and the role of these particles in phenomena like noctilucent clouds and polar mesospheric summer echoes (PMSE). The mesopause region, situated between $\sim 80$ and 90 km, contain a variety of different particle types such as ice particles, meteoric smoke particles (MSPs) and hybrids of these. The role of such particles in a number of processes in the mesopause and further down in the atmosphere is not well understood. This work aims to close some of the gaps in our current understanding mainly by using aerosol detectors of the Faraday cup type. For this purpose, we have developed new observational techniques using such probes, which makes it possible to obtain information on intrinsic particle properties such as charge state, size and number density of both ice and MSPs. The configuration and technical capabilities of the probes on MAXIDUSTY also allows for observation of spatial structures in the dusty plasma down to scales of $\sim 10$ cm. Notably, we are able to calculate the size distribution and charge state of ice particles on scales well below 1 metre. With the impact probe MUDD, we are able to infer the size distribution and volume content of MSPs embedded in larger ice particles. We moreover present the first observations of mesospheric clouds situated well below the summer mesopause, at altitudes between $66$ and 78 km, which implies a significant updraft in this region. From a thorough investigation into spatial fluctuations on different length scales, we find that the aerosol-electron coupling is changing throughout a cloud system and not strictly anti-correlated. We also find that a simple relationship between PMSE and dusty plasma parameters is not possible to obtain from MAXIDUSTY measurements. To sonderaketter ble ...