Dust dynamic pressure and magnetopause displacement: reasons for non-detection

Abstract

Abstract. In a recent paper, Treumann and Baumjohann (2011) propose that the contribution of dust particles to the solar wind dynamic pressure can cause large compressions of the Earth's magnetopause and suggest that this occurs when Earth encounters meteoroid streams. In this paper we estimate the contribution from charged dust particles to the solar wind dynamical pressure, and we exclude that the dust associated to meteoroid streams can influence the extension of the magnetopause according to the proposed model. A sufficient coupling to the solar wind is only expected for so-called nanodust. However, the dynamic pressure of the nanodust is orders of magnitudes below that of the solar wind, making it unlikely that its variation can be observed in displacements of the magnetopause. We also discuss the equation that the authors use for estimating the extension of the Earth's magnetopause, and conclude that this is not applicable due to the large gyroradius of the nanodust. We finally note that an influence of dust on the extension of a magnetosphere might be quite possible in other astrophysical systems and based on other processes.

Division E Commission 49: Interplanetary Plasma and Heliosphere

“…The acceleration bears some simillarities to the ion pick-up process and a basic understanding of the nanodust dynamics in the solar wind and at the edge of the heliosphere can be obtained from applying the guiding center approximation (Mann et al (2014)), while more detailed studies are in progress. In spite of the large velocity the nanodust momentum flux in the solar wind is small and for instance it does not influence the magnetosphere of the Earth (Mann & Hamrin(2013)). The interstellar dust measurements with the Ulysses spacecraft have been subject to a large number of publications and discussed in previous reports.…”

Intrinsic fluctuations of dust grain charge in multi-component plasmas

“…The assumed plasma is the most general case of a plasma in terms of the involved components. Some applications relevant to the problem considered here have been identified: In the solar system, interstellar dust gains are charged by electrons, protons, and alpha particles [11][12][13] . In addition to these ions, other highly charged ions of carbon, oxygen, and nitrogen contribute to the charging of dust in the solar wind plasma 14,15 .…”