Articles | Volume 35, issue 4
Ann. Geophys., 35, 979–998, 2017
Ann. Geophys., 35, 979–998, 2017

Regular paper 24 Aug 2017

Regular paper | 24 Aug 2017

Estimate of size distribution of charged MSPs measured in situ in winter during the WADIS-2 sounding rocket campaign

Heiner Asmus1, Tristan Staszak1, Boris Strelnikov1, Franz-Josef Lübken1, Martin Friedrich2, and Markus Rapp3,4 Heiner Asmus et al.
  • 1Leibniz Institute of Atmospheric Physics, Kühlungsborn, Germany
  • 2Graz University of Technology, Graz, Austria
  • 3Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
  • 4Meteorologisches Institut München, Ludwig-Maximilians-Universität München, Munich, Germany

Abstract. We present results of in situ measurements of mesosphere–lower thermosphere dusty-plasma densities including electrons, positive ions and charged aerosols conducted during the WADIS-2 sounding rocket campaign. The neutral air density was also measured, allowing for robust derivation of turbulence energy dissipation rates. A unique feature of these measurements is that they were done in a true common volume and with high spatial resolution. This allows for a reliable derivation of mean sizes and a size distribution function for the charged meteor smoke particles (MSPs). The mean particle radius derived from Schmidt numbers obtained from electron density fluctuations was ∼ 0.56 nm. We assumed a lognormal size distribution of the charged meteor smoke particles and derived the distribution width of 1.66 based on in situ-measured densities of different plasma constituents. We found that layers of enhanced meteor smoke particles' density measured by the particle detector coincide with enhanced Schmidt numbers obtained from the electron and neutral density fluctuations. Thus, we found that large particles with sizes  > 1 nm were stratified in layers of  ∼ 1 km thickness and lying some kilometers apart from each other.

Short summary
This work sheds new light on the size distribution of dust grains of meteoric origin in the mesosphere and lower thermosphere region using rocket-borne instrumentation. We found that a large number of very small (~ 0.5 nm) particles are charged and therefore have a significant influence on the charge balance of the lower ionosphere.