I will discuss the best instrument systems that have worked well in the past to provide heliospheric remote sensing analyses, and which promise the most significant future advances from this work. Heliospheric remote sensing began in Cambridge, England, with the use of interplanetary scintillation (IPS) data in the 1960' s. Studies using IPS have continued at UCSD and Japan from the 1970' s onward, and in the middle of the 1990s' several iterative three-dimensional (3-D) tomographic reconstruction techniques developed by both M. Kojima of ISEE, Japan, and the UCSD group independently, gave rise to the first iterative tomographic analyses. These IPS analyses have been used to refine and provide a space weather forecast capability for plasma velocities, densities, and magnetic fields. The UCSD group developed this technique further in a time-dependent form to provide a 3-D heliospheric analyses from Thomson-scattering data obtained by the Solar Mass Ejection Imager (SMEI, 2003 - 2011), and more recently has incorporated the inclusion of 3-D MHD analyses in this process. Now to provide even higher spatial and temporal resolutions and more complete coverage, the UCSD tomographic system can incorporate multi-perspective spacecraft views using Thomson scattering data as well as different Earth longitude IPS data sets.
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