STEREO A Heliospheric Imager and Interplanetary Scintillation Observations Now Provide Near Real Time 3-D High-Resolution Density and Velocity Reconstructions of the Inner Heliosphere
Abstract
We have recently adapted the UCSD Solar Mass Ejection Imager (SMEI) iterative tomography analyses for use with STEREO Heliospheric Imager (HI) data to provide 3-D reconstructed plasma densities of the inner heliosphere in the region viewed by these instruments. These analyses also include interplanetary scintillation (IPS) Earth-based instrumentation data from ISEE, Japan, to help provide more comprehensive analyses of both high-resolution density and velocity. As STEREO A approaches the Earth over the coming year, this provides an unprecedented ability to reconstruct densities in that portion of the inner heliosphere Earthward of the Sun, and allows an ahead-of-time prediction of plasma density properties in this region. Because we are using HI data with a long temporal base removed, both Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs) are among the phenomena that can be revealed by the analyses. Here we present this near real time system operation that, albeit limited by the fact that the latency of the current STEREO HI scientific image data is three to five days, provides 3-D reconstructions of the plasma density and its determination. These densities can be obtained at any location throughout the inner heliospheric region imaged, and radially extrapolated outward from them. The reconstructions are updated every six hours, which is well within the time limit needed for actionable forecasts of the arrival of the fastest heliospheric structures at Earth. This system benchmarks computing needs for high-resolution 3-D reconstruction analyses of this type. It prototypes the forecasting capability for future similar spacecraft heliospheric imager instruments such as the NASA Small Explorer PUNCH, UCSD's All Sky Heliospheric Imager (ASHI), or the Lagrange (Vigil) Heliospheric Imager that are intended to be operated with a shorter data latency.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.1085J