The investigators will conduct observational and theoretical studies of meteoroid-related processes in the mesosphere and lower thermosphere (MLT). The study will utilize observations at the six NSF radars (and associated lidars), as a diversity of frequencies, viewing angles relative to the geomagnetic field, and latitudes/seasons is required to determine the whole earth meteoroid mass flux, explore the head/trail-echo scattering mechanisms, and to reveal details of the meteoroid interaction with the atmosphere including fragmentation, ablation, sputtering, and the resultant plasma physics and aeronomic effects. The complex role of the meteoroid mass flux to the Mesosphere & Lower-Thermosphere (MLT) on the aeronomy and electrodynamics of this region as represented by, e.g., sporadic-E, sporadic metal layers, and Polar Mesospheric Summer Echoes (PMSE), remains an illusive and even unrecognized component of space weather. Detailed understanding of the radio science of the radar head/trail-echo radar scattering processes is required to correctly interpret how the plasma surrounding the meteoroid--and that then forms the meteor trail--is generated and evolves, thus revealing important insights into sputtering, fragmentation, and terminal processes. Details of these processes remain a source of controversy. The investigators will also study how the meteoroid metals arrive in tidal ion, sporadic-E layers, noctilucent clouds, and PMSE. Modern high-power, large-aperture (HPLA) radar meteor observations have greatly stimulated the entire field of meteor physics and associated aeronomy. Observational and modeling/simulation studies of the radar meteor head/trail-echo scattering processes provide unique insight into meteoroid interaction with the atmosphere and also into the contribution of meteoric ions and 'smoke' to the ionospheric D- and E-regions. The observations will provide details on how the meteoroid plasma trail evolves into geomagnetic field aligned plasma structures and will explore the surprising and instructive meteoroid flare generated plasma waves that produce non-thermal radar scattering. Together with radar observations, Rayleigh and metal lidar results provide a new dimension to meteoroid flux aeronomic studies. The meteoroid flux into the MLT is linked to solar system and local galactic processes. These are 'systems of systems' space weather issues where meteoroid energy dissipation heating of the upper atmosphere is of the same order as Joule and particle heating of the auroral zones--an apparently unrecognized property of the meteoroid flux. This study will also lead to the development of new radar imaging techniques and help address issues such as the role of the meteoroid mass flux in many lower atmospheric processes such as cloud formation and stratospheric chemistry. Exploration of meteor-related electrodynamics and non-equilibrium plasma physics may stimulate other areas of research in, for example, the ionospheric heating community. This research will involve both graduate and undergraduate researchers, featuring discovery and learning to communicate knowledge concerning the meteoroid processes, related spaceweather and systems issues, and associated aeronomy.
|Effective start/end date||9/15/12 → 8/31/16|
- National Science Foundation: $559,998.00