The Suprathermal Population in the Interplanetary Medium: Importance to Space Weather Forecasting
Abstract
Advances in heliospheric ion measurements in the suprathermal (ST) energy range (above the bulk solar wind protons) over the past two decades have significantly improved our understanding of this particle regime. Most importantly, in situ spacecraft measurements have provided compelling evidence for the ubiquitous presence of ST spectral tails, from which extreme Space Weather events, such as Solar Energetic Particles (SEPs), draw their accelerating material. Despite their increased level of importance for Space Weather and SEP-related predictions, the origin, properties, and acceleration processes of these ST particles remain highly controversial. Current physics-based SEP propagation and acceleration models require information about the ST seed spectrum as part of their input. While some modelers use a pre-defined analytic spectral form as input, others utilize measurements of the ambient properties near 1 AU to infer a scaled ST seed input. Both approaches of estimating the seed spectrum are heuristic and present rough estimates. The need of a realistic seed ST spectrum is thus critical to improve SEP predictions near 1 AU and beyond. As part of COSPAR International Space Weather Action Teams (ISWAT; Radiation environment in heliosphere cluster; H3), Our H3-02 Action Team aims at further understanding the ST population and exploring the feasibility of determining a reliable seed spectrum that can be used by SEP modelers. We utilize multi-spacecraft observations and a set of validated modeling and simulation tools. This talk presents an overview of the topic and addresses the challenges and mitigations pertaining to the team objective.
- Publication:
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43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E2400D