Abstract
Abstract AniMAIRE (Anisotropic Model for Atmospheric Ionising Radiation Effects) is a new model and Python toolkit for calculating radiation dose rates experienced by aircraft during anisotropic solar energetic particle events. AniMAIRE expands the physics of the MAIRE + model such that dose rate calculations can be performed for anisotropic solar energetic particle conditions by supplying a proton or alpha particle rigidity spectrum, a pitch angle distribution, and the conditions of Earth's magnetosphere. In this paper, we describe the algorithm and top‐level structure of AniMAIRE and showcase AniMAIRE's capabilities by analyzing the dose rate maps that AniMAIRE produces when the time‐dependent spectra and pitch angle distribution for Ground Level Enhancement (GLE) 71 are input. We find that the dose rates AniMAIRE produces for the event fall between the dose rates produced by the WASAVIES and CRAC:DOMO models. Dose rate maps that evolve throughout the event are also shown, and it is found that each peak in the input pitch angle distribution generates a dose rate hotspot in each of the polar regions. AniMAIRE has been made available openly online so that it can be downloaded and run freely on local machines and so that the space weather community can easily contribute to it using Github forking.
Plain Language Summary Solar particle events occur when particles are accelerated in eruptions on the Sun. If these particles hit Earth and have enough energy, they can penetrate Earth's magnetosphere and atmosphere, creating radiation showers that increase the radiation in Earth's atmosphere. When such increases are detected by neutron monitors at sea level, they are known as Ground‐Level Enhancements (GLEs), which occur once a year on average. GLEs can cause issues in aircraft electronics and cause passengers and crew on airplanes to experience heightened radiation doses. In this paper, we describe a new model to calculate radiation dose rates in the atmosphere during GLEs, called AniMAIRE. Most models that exist to date are only able to calculate radiation dose rates when all particles are hitting Earth equally from all directions, however this approximation is only reliable during the later stages of events, and isn't accurate for many GLEs. AniMAIRE has been designed so it doesn't need to rely on this approximation, and can calculate dose rates for situations where it is supplied a direction‐dependent particle flux, as well as those independent of direction. AniMAIRE has been tested across a GLE in May 2012, showing the direction dependent approach is necessary.
Key Points AniMAIRE can simulate atmospheric radiation and electronics effects from anyinput anisotropic distribution of particles hitting Earth Anisotropy is important in the event‐integrated dose calculation for GLE71 according to AniMAIRE AniMAIRE has been made openly available online, such that anyone can run and experiment with it, or contribute to the model through forking