This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
In this work, the Principal Investigator (PI) will use interplanetary scintillation (IPS) radio data collected by an international network of ground-based radio telescopes and antenna arrays, as well as Thomson-scattered white-light observations from space-based instruments on the Solar Mass Ejection Imager (SMEI) and STEREO spacecraft, in order to develop 3D tomographic reconstructions of solar plasma structures in the inner heliosphere. Such structures include coronal mass ejections (CMEs) and co-rotating interaction regions (CIRs).
The PI will extract solar wind parameters such as velocity, density, and magnetic field from his 3D reconstructions and compare these with multi-point in situ solar wind measurements from spacecraft such as ACE, STEREO, Ulysses, and Wind. The PI's 3D reconstructions can also be used to better constrain analyses of extremely-long-baseline (ELB) IPS observations, such as those recorded by the European Incoherent SCATter (EISCAT) radar, the EISCAT Svalbard Radar (ESR), and the Multi-Element Radio-Linked Interferometer Network (MERLIN) radio telescopes. This PI also has well-established links to IPS research groups at STELab in Japan and the Ootacamund Radio Telescope in India. Because of his multiple international collaborations, the PI has unique experience with such ELB analyses, which will allow the extraction of finer details in plasma spatial structure using images from spacecraft.
The broader impacts of this study are manifold. The 3D reconstructions and ELB analyses planned here offer the potential to transform the field of heliospheric physics, by providing a global context for discovering the physical principles underpinning space weather phenomena that affect the Earth. The PI's technique makes visible a region between the Sun and the Earth whose behavior is difficult to forecast. The 3D reconstruction method improves space weather forecasts in this region, and will make them more accurate. The 3D reconstruction images and movies that are produced by this approach provide a valuable educational tool, as well as an aid to planning future spacecraft missions and new ground-based observatories.
