"Shockwaves in Space: Can One Satellite Tell Us What's Coming, or Do We Need a Fleet?"

Abstract: Interplanetary shocks in our solar system are driven by solar eruptions and solar wind stream interactions. When directed at Earth, these shocks interact with Earth’s magnetosphere, with ramifications that vary depending on the magnitude of the shock wave and the conditions presenting upstream. To forecast and mitigate their impact on the Earth, it is important that we can measure the magnitude and the attack angle of an interplanetary shock wave arriving at the Earth. These shock waves are independently observed and measured en route to the Earth at Wind, the Deep Space Climate Observatory (DSCOVR), the Solar Heliospheric Observatory (SOHO), and the Advanced Composition Explorer (ACE). In this project, we propose a new method of analysis using a multi-spacecraft fleet to characterize these shock waves. We compare two different methods for estimating the propagation vector of a shock prior to its arrival at Earth: a single spacecraft analysis using Wind and a multi-spacecraft geometric analysis using Wind, DSCOVR, SOHO, and ACE.  

Potential interplanetary shock waves are first cataloged in the Center for Astrophysics Interplanetary Shock Database by searching for abrupt jumps in the plasma and magnetic parameters. For each candidate, we follow the methodology of Szabo et al, 2004 and Viñas and Scudder, 1986 to determine the most probable propagation vector and whether the candidate represents a shock transition. We then corroborate the event in observations from ACE, DSCOVR, and SOHO. Using the set of four positions and times of shock observation, the shock’s magnitude and direction of propagation is fully determined under the assumption of planar geometry. We use this method to benchmark the performance of the single spacecraft analysis for different types of shocks, and we evaluate the relative utility of a single in situ L1 monitor versus a constellation for space weather forecasting. This work is supported by the NSF-REU solar physics program at SAO, grant number AGS-2244112.