Abstract
AbstractSevere space weather was identified as a risk to the UK in 2010 as part of a wider review of natural hazards triggered by the societal disruption caused by the eruption of the Eyjafjallajökull volcano in April of that year. To support further risk assessment by government officials, and at their request, we developed a set of reasonable worst‐case scenarios and first published them as a technical report in 2012 (current version published in 2020). Each scenario focused on a space weather environment that could disrupt a particular national infrastructure such as electric power or satellites, thus, enabling officials to explore the resilience of that infrastructure against severe space weather through discussions with relevant experts from other parts of government and with the operators of that infrastructure. This approach also encouraged us to focus on the environmental features that are key to generating adverse impacts. In this paper, we outline the scientific evidence that we have used to develop these scenarios, and the refinements made to them as new evidence emerged. We show how these scenarios are also considered as an ensemble so that government officials can prepare for a severe space weather event, during which many or all of the different scenarios will materialize. Finally, we note that this ensemble also needs to include insights into how public behavior will play out during a severe space weather event and hence the importance of providing robust, evidence‐based information on space weather and its adverse impacts.
Highlights
The past decade has seen increased awareness of the need for societal resilience against the full range of natural hazards that can seriously disrupt everyday life
Hapgood et al (2020): Section 7.15 discusses the neutron fluxes that can led to significant rates of single event effects in avionics, Section 7.16 which discusses how these neutron fluxes can accumulate to deliver significant radiation doses to aircrew and passengers; and Section 7.7 which complements Section 7.15 by discussing the ground level neutron fluxes that can lead to SEEs in electronic systems on the surface of the Earth
Severe space weather was formally recognized as a significant natural hazard in the UK in 2011, because scientific evidence, as outlined here, showed that severe space weather conditions are to be expected on similar timescales to extremes of other natural hazards considered in the UK National Risk Register (Cabinet Office, 2017)
Summary
When high-energy particles strike the Earth's atmosphere they can interact with the nuclei of oxygen and nitrogen to generate a cascade of secondary particles including neutrons, protons, electrons, and muons. The secondary radiation builds up to a maximum at around 60,000 feet (18 km) and attenuates down to sea level This secondary radiation includes both a slowly changing background due to GCRs and episodic increases when SEP events contain significant fluxes of very high-energy particles. Secondary radiation from particles with energies above 400 MeV can reach aircraft cruising altitudes and sea level. The latter class of events occurs approximately once per year and is known as a ground level enhancement (GLE). The secondary radiation from GCRs is an important practical issue for aviation It is a continuous effect, slowly changing in response to changes in GCR fluxes; we do not consider it as part of this worst-case scenario. We focus on the enhanced secondary radiation fluxes generated by SEP events
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