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<div style="color:rgb(0,0,0)">Dear colleagues,</div>
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<div>We would like to draw your attention to the <font color="#0000ff"><strong>Meteoroids and Space Debris</strong></font> session at CEDAR, convened by Julio Urbina and Sigrid Close. If interested in presenting, please email the conveners with your title/topic
and requested time allotment. We welcome all participation! <strong style="color: rgb(0, 111, 201);">
<span style="color: rgb(0, 111, 201);"><span style="color: rgb(0, 111, 201);">The session is on June 24, Friday Morning 08:00-10:00;
</span></span></strong><strong style="color: rgb(0, 111, 201);"><span style="color: rgb(0, 111, 201);"><span style="color: rgb(0, 111, 201);">Sweeney D.</span></span></strong><br>
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<div style="color:rgb(0,0,0)"><span style="font-family:sans-serif;font-size:13px;line-height:19.049999237060547px;background-color:rgb(255,255,255)">Billions of particles from the Sporadic Meteoroid Complex (SMC) end their journey through the solar system when
they fatally impact the Earth’s upper atmosphere. This results in the deposition of mass, momentum and energy in the transition region of the ionosphere between the D and E region where the neutral atmosphere begins to play an important role in the evolution
of the plasma environment due to ion-neutral collisions. This ablated material (whose mass loading of the upper atmosphere is still uncertain to within 2 orders of magnitude) results in the neutral metal layers traditionally observed between 85-105 km using
lidar and plays an important role in the atomic chemistry of mesospheric metals. In addition, ablated constituents from the micrometeoroid particles sediment and condense to form meteoric smoke particles. This dusty plasma in the D region is a source of the
condensation nuclei (CN) for ice layer-related phenomena such as: Polar Mesospheric Clouds and Polar Mesospheric Summer Echoes (PMSEs). The CN as well as the related phenomena are influenced by the forcing of the neutral winds and tides as well as chemistry.
Through the action of advection, down-welling and meridional circulation these CN are transported into the lower atmosphere and contribute to phenomena such as Polar Stratospheric Clouds and stratospheric aerosols. Furthermore, these small particles act as
a transport mechanism of mesospheric metals to the Earth's surface and ocean. It is also worth noting that larger meteoric particles that survive the ablation process in the upper atmosphere provide a space weather hazard in the form of impacts as well as
iron rich materials that are deposited in the ocean. Viewing Earth-Atmosphere-Geospace coupling and interactions as a complete and interactive system, meteors contribute across a wide range of spatial and temporal scales as both a driver and catalyst of significance
to microphysics and phenomena. Meteors are routinely observed using a wide array of observational techniques in both the neutral and plasma environment and can be used as a tracer to study background parameters such as neutral winds, temperatures and tides.
Many open questions exist in the meteor field. These range from gaps in fundamental understanding such as: what is the scatter process that results in radar observed meteor head echoes? and what is the mass loading of the upper atmosphere by meteor ablation
and why do estimates very so drastically? to more nuanced questions about the relationship between meteor properties defined by the meteor input function and atmospheric phenomena tied to meteors. As with any study that uses the tools of system dynamics and
system science one must first define the system (i.e. defining the boundaries, inputs and outputs in a thermodynamic system) and then make the simplifying assumptions that yield the relevant physics to the problem at hand. For meteor related studies, this
system definition has often been implicit and related to boundaries defined by meteor ablation heights. But, as our measurement capability and knowledge increases regarding the SMC, we continue to push these traditional boundaries to uncover new insight into
the processes, drivers, and feedbacks related to meteors within the Earth-Atmosphere-Geospace system allowing us to learn more about the coupling and interactions that can be uncovered using meteor science.</span></div>
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<div style="color:rgb(0,0,0)">Prof. Julio Urbina (<a href="mailto:JUrbina@engr.psu.edu" target="_blank">JUrbina@engr.psu.edu</a>)</div>
<div style="color:rgb(0,0,0)">Prof. Sigrid Close (<a href="mailto:sigridc@stanford.edu" target="_blank">sigridc@stanford.edu</a>)</div>
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