ABSTRACT

The PI has developed a tomographic technique to study the heliosphere and solar wind in three dimensions. This effort would provide photometric sky maps from Solar Mass Ejection Imager (SMEI) data and continue to update the required data processing techniques, so that the SMEI data could be used to map solar wind structures in three dimensions. These sky maps, if sufficiently accurate, could be used for forecasting and many other space weather projects, and the PI's team would help provide calibrated data to users.

Intellectual Merit: The proposed basic research effort would involve the analysis of SMEI data (available in near real time) that indicates the density of heliospheric plasma. The now operational USAF-UCSD-Birmingham UK Solar Mass Ejection Imager (SMEI) provides these data every orbit. The PI's primary goal is the real time three-dimensional reconstruction and visualization, using tomographic methods, of plasma structures interacting with the Earth. These reconstructions would help answer questions concerning the shape of solar wind structures in geospace and their interaction with the ambient solar wind plasma. However, to do this, the PI must develop new analysis techniques to deal with the SMEI image frame data. These image frames must be combined into composite sky map images for use photometrically. By doing this, the PI would determine the brightness of the sky background to a never-before achieved accuracy at the SMEI orbital data-taking cadence. This proposed effort requests funds to make these data available to those who wish to use them.

Broader Impact: This work would have a broad impact on solar-terrestrial physics and astronomy. This SMEI effort would render visible the region between Sun and Earth that has previously been exceedingly difficult to depict and study. The composite images produced in near real time could be directly understood by those not in the field of solar physics, improving public outreach. These images would provide a valuable educational tool, as well as a heliospheric forecast capability and a means to study the global properties of interplanetary CMEs, co-rotating plasma structures, and solar wind interactions. The PI would make the data archive (3D volumes, composite images, and software needed to manipulate them) available to the entire heliospheric and space weather community. Given that SMEI currently images the solar atmosphere all around the Earth, this work would usher in a new era for viewing space from Earth as a planet embedded within the heliosphere, and for modeling and understanding solar-terrestrial connections. SMEI data allow views of the sidereal sky around the Earth globally and photometrically, providing point-source measurements of stars, galaxies, and star clusters with unprecedented precision. The data set could also be used to study the brightness changes, anomalous structure, and long-term stability of the zodiacal dust cloud, which is of intrinsic interest to astronomers and particular interest to those designing space-based optical sensors. The PI's team would provide SMEI data access for academic, research, and non-profit purposes.

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