Imaging Geospace Electrons Using Thomson Scattering

1. Imaging Geospace Electrons Using Thomson Scattering R. R. Meier, D. Chua (damien.chua@nrl.navy.mil), C. Englert, D. Socker, J. M. Picone, T. Carter, J. Huba, S. Slinker, J. Krall, and W. Vincent, Naval Research Laboratory, Washington, DC • Science Objectives: • Determine how electrons in the magnetosphere, plasmasphere, and ionosphere are redistributed in response to solar wind forcing. • Understand mechanisms of solar wind plasma entry into the magnetosphere by globally imaging structures along the magnetopause and magnetospheric boundary layers. • Determine how variations of the duskside plasmasphere and plasmapause are coupled to the global dynamics of the magnetosphere. • Establish sensitivity of space weather forecasts to initial conditions in the magnetosphere and provide global boundary conditions to geospace specification models. • Associated RFAs • RFA H.2 - Determine changes in the Earth’s magnetosphere, ionosphere, and upper atmosphere to enable specification, prediction, and mitigation of their effects • RFA J.4 – Understand and characterize the space weather effects on and within planetary environments to minimize risk in exploration activities. We can observe disruptive solar events such as CMEs from the sun through the heliosphere (above, left). Thomson scattering observations of geospace electrons will complete our chain of Sun-to-Earth observations, enabling global specification and forecasts of the ionosphere-plasmasphere-magnetosphere system in response to solar drivers. Simulated Thomson scattering signals from geospace electrons, bottom right, show the bow shock, magnetosheath, magnetopause, and the plasmasphere from the SAMI3-LFM model. • Mission Implementation Description: • One 3-axis stabilized spacecraft • 30-RE circular, inertial polar orbit • Four imagers (two “geo-coronagraphs”, two white-light, magnetospheric imagers) • Payload mass (instruments and spacecraft): 1700 kg • Measurement Strategy: • Observe Thomson scattered light to directly image geospace electron densities and their interactions with the solar wind • Enabling and Enhancing Technology Development: • NRL-built coronagraphs and STEREO SECCHI/Heliospheric Imagers have successfully imaged structures in the solar wind (CMEs and CIRs) by observing Thomson scattered light. We will adapt these techniques to directly image geospace electrons for the first time. • Other enabling technologies required for this mission: • Large format focal plane detector arrays • Light-weight large optics • Formation flying satellites (potentially) • Next generation space environment forecasting models that include and couple all regions of geospace out to the bow shock, magnetosheath, and magnetopause regions.