Realistic Worst Case for a Severe Space Weather Event Driven by a Fast Solar Wind Stream.

Richard B Horne,Alex D P Hands,Nigel P Meredith,Keith A Ryden,Sarah A Glauert,Wen Li,Mark W Phillips

doi:10.1029/2018sw001948

Abstract

Satellite charging is one of the most important risks for satellites on orbit. Satellite charging can lead to an electrostatic discharge resulting in component damage, phantom commands, and loss of service and in exceptional cases total satellite loss. Here we construct a realistic worst case for a fast solar wind stream event lasting 5 days or more and use a physical model to calculate the maximum electron flux greater than 2 MeV for geostationary orbit. We find that the flux tends toward a value of 106 cm−2·s−1·sr−1 after 5 days and remains high for another 5 days. The resulting flux is comparable to a 1 in 150‐year event found from an independent statistical analysis of electron data. Approximately 2.5 mm of Al shielding would be required to reduce the internal charging current to below the National Aeronautics and Space Administration‐recommended guidelines, much more than is currently used. Thus, we would expect many satellites to report electrostatic discharge anomalies during such an event with a strong likelihood of service outage and total satellite loss. We conclude that satellites at geostationary orbit are more likely to be at risk from fast solar wind stream event than a Carrington‐type storm.

Highlights

Our reliance on satellites for applications such as mobile phones, broadcasting, navigation, and timing signals is growing substantially
The resulting spectrum was used as the initial condition and the model was run with Bw1 = 31 pT for 5 days followed by Bw2 = 7 pT for 5 days without substorm injections to represent low activity after the fast solar wind stream had passed
We have developed a model to calculate the maximum electron flux greater than 2 MeV at L∗ = 6 for an extreme space weather event driven by a fast solar wind stream

Summary

Introduction

Our reliance on satellites for applications such as mobile phones, broadcasting, navigation, and timing signals is growing substantially. As a result there has been a growing concern about the impact of a severe space weather event and the disruption it could cause. A recent study found that 10% of the entire satellite fleet suffered anomalies (malfunctions) during the so-called Halloween storm of 2003 (Cannon et al, 2013) resulting in loss of service and in one case total satellite loss. Assuming that the same percentage of satellites would be affected, approximately 150 spacecraft would be disrupted if a similar storm took place today. The 2003 Halloween storm was by no means as big as the 1859 Carrington storm, and so for an extreme event the number of satellites affected could be much higher, but remains very uncertain

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