EGU2020-1805
https://doi.org/10.5194/egusphere-egu2020-1805
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Dust detection by antenna instruments

Zoltan Sternovsky1, Ming-Hsueh Shen1, Michael DeLuca1, Åshild Fredriksen2, Mihály Horányi1, Sean Hsu1, Samuel Kočiščák3, David Malaspina1, Libor Nouzák3, and Shengyi Ye4
Zoltan Sternovsky et al.
  • 1LASP, University of Colorado, Boulder, United States of America (zoltan.sternovsky@colorado.edu)
  • 2Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø, Norway
  • 3Department of Surface and Plasma Science, Charles University, Prague, Czech Reppublic
  • 4Department of Earth and Space Sciences, SUSTech, Shenzhen, China

Antenna instruments on space missions have been used to detect dust particles and characterize dust populations. The antennas register the transient electric signal generated by the expansion of the impact plasma from the dust impact on the spacecraft body or the antenna. Given the large effective sensitive area, antenna instruments offer an advantage over dedicated dust detectors for dust populations with low fluxes. The dust accelerator facility operated at the University of Colorado has been employed to investigate the physical mechanisms of antenna signal generation. The dominant mechanism is related to the charging of the spacecraft (or antenna) by collecting some fraction of electrons and ions from the impact plasma. We have carried out a number of experimental campaigns in order to characterize the dust impact charge yields from relevant materials, the effective temperatures of dust impact plasmas, and variations of the antenna signals with spacecraft potential, or magnetic field. Here we report on a physical model that provides a good qualitative and quantitative description of the antenna waveforms recorded in laboratory conditions. The model is based on the separation of the electrons from the ions in the impact plasma and their different timescales of expansion. The escaping and collected fractions of charges are driven by the spacecraft potential. Fitting the model to the laboratory data revealed that the electrons in the impact plasma have an isotropic distribution, while ions are dominantly moving away from the dust impact location. Identifying the fine details in the antenna signals requires a relatively high sampling rate and thus not commonly resolved for past instruments. The high-rate mode of the FIELDS instrument on the Parker Solar Probe, however, can be used to verify the proposed model.

How to cite: Sternovsky, Z., Shen, M.-H., DeLuca, M., Fredriksen, Å., Horányi, M., Hsu, S., Kočiščák, S., Malaspina, D., Nouzák, L., and Ye, S.: Dust detection by antenna instruments, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1805, https://doi.org/10.5194/egusphere-egu2020-1805, 2019