Nano-Dust Analyzer

Recently, the STEREO WAVES instruments recorded a large number of intense electric field signals, which were interpreted as impacts from nanometer sized particles striking the spacecraft with velocities of about the solar wind speed [1]. This high flux and strong spatial and/or temporal variations of nanometer sized dust grains at low latitude appears to be uncorrelated with the solar wind properties. Early dust instruments onboard Pioneer 8 and 9 and Helios spacecraft detected a flow of submicron sized dust particles coming from the direction of the Sun. These particles originate in the inner solar system from mutual collisions among meteoroids and move on hyperbolic orbits that leave the Solar System under the prevailing radiation pressure force [2]. The observed fluxes of inner-source pickup ions also point to the existence of a much enhanced dust population in the nanometer size range [3]. A new highly sensitive instrument is being developed within NASA's Heliophysics Program to confirm the existence of the so-called nano-dust particles, characterize their impact parameters, and measure their chemical composition. The instrument is based on the Cassini Dust Analyzer (CDA) that has analyzed the composition of nanometer sized dust particles emanating from the Jovian and Saturnian systems but could not be pointed towards the Sun. By applying technologies implemented in solar wind instruments and coronagraphs a highly sensitive dust analyzer will be developed and tested in the laboratory. The measurements will enable us to identify the source of the dust by comparing their elemental composition with that of larger micrometeoroid particles of cometary and asteroid origin and will reveal interaction of nano-dust with the interplanetary medium by investigating the relation of the dust flux with solar wind and IMF properties. [1] Meyer-Vernet, N. et al., Solar Physics, 256, 463, 2009 [2] Zook, H.A. and Berg, O.E.: A source for hyperbolic cosmic dust particles. Planetary and Space Science, 23 (1975) 183-203. [3] Schwadron, N. A., et al., J. Geophys. Res., 105, 7465, 2000.