Storm-Time Cusp Precipitation: Insights from TRACERS Multi-Crossing Observations

Shirsh Lata Soni; David M Miles; Jasper Halekas; Stephen A Fuselier; George Hospodarsky; Marit Øieroset; K. J Trattner; S. M Petrinec; Jeremy Faden; Ivar Christopher; Chris Pikar; Sarah A Henderson; Daniel Da Silva; Scott Bounds; Robert Strangeway

doi:10.48550/arxiv.2605.30620

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Storm-Time Cusp Precipitation: Insights from TRACERS Multi-Crossing Observations

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Storm-Time Cusp Precipitation: Insights from TRACERS Multi-Crossing Observations

Shirsh Lata Soni, David M Miles, Jasper Halekas, Stephen A Fuselier, George Hospodarsky, Marit Øieroset, K. J Trattner, S. M Petrinec, Jeremy Faden, Ivar Christopher, …

ArXiv.org

Cornell University

05/28/2026

DOI: 10.48550/arxiv.2605.30620

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Preprint (Author's original) This preprint has not been evaluated by subject experts through peer review. Preprints may undergo extensive changes and/or become peer-reviewed journal articles. Open Access

Abstract

The dayside cusp provides a direct pathway for solar wind plasma entry into the magnetosphere ionosphere system through magnetic reconnection. Using low altitude ion and electron measurements from TRACERS, together with upstream solar wind and geomagnetic conditions, we investigate the evolution of the cusp during a geomagnetic storm on 30 September 2025, spanning its rising, main, and recovery phases, and compare these with a quiet-time reference. Storm-time observations show broader and more poleward precipitation regions and enhanced electron energy flux, indicating intensified dayside coupling. To interpret these variations, we combine solar wind and IMF measurements with the maximum magnetic shear reconnection model to determine X-line locations and use a Tsyganenko field model to compute event-specific field-line transit distances between the X-line and TRACERS. The results demonstrate that cusp morphology and latitude track IMF-driven reconnection geometry, and that realistic path lengths are essential for quantitative reconnection-rate estimates, highlighting the capability of TRACERS to resolve storm-time cusp evolution. Enhanced cusp precipitation during the recovery phase is consistent with IMF conditions, indicating sustained solar wind driving rather than intrinsic storm-phase effects.

Physics - Space Physics

Details

Title: Subtitle: Storm-Time Cusp Precipitation: Insights from TRACERS Multi-Crossing Observations
Creators: Shirsh Lata Soni
David M Miles
Jasper Halekas
Stephen A Fuselier
George Hospodarsky
Marit Øieroset
K. J Trattner
S. M Petrinec
Jeremy Faden
Ivar Christopher
Chris Pikar
Sarah A Henderson
Daniel Da Silva
Scott Bounds
Robert Strangeway
Resource Type: Preprint
Publication Details: ArXiv.org
DOI: 10.48550/arxiv.2605.30620
ISSN: 2331-8422
Publisher: Cornell University; Ithaca, New York
Language: English
Date posted: 05/28/2026
Academic Unit: Physics and Astronomy
Record Identifier: 9985167652702771

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