Transfer Learning Aurora Image Classification and Magnetic Disturbance Evaluation

Abstract

Created by particles precipitating into the ionosphere, the aurora are a direct consequence of interactions between the solar wind and the magnetosphere. A connection between different auroral shapes and behaviors simultaneously across the polar region has been first shown in 1964, when analyzing auroral images taken across northern continental America and Antarctica (Akasofu, 1964). The established model of auroral substorms, describes the activity of the aurora from its beginning, when the aurora is calm, over active phases toward another calm phase. This model was later refined to include the three currently used phases "growth", "expansion" and "recovery" (McPherron et al., 1973). Interaction between the solar wind and the interplanetary magnetic field lead to storage of energy in the magnetosphere during the growth phase. In the expansion phase energy is released, before the magnetosphere returns to normal conditions in the recovery phase.Since the beginning of auroral research, images have therefore been an important tool to analyze and diagnose the complex processes in the ionosphere and magnetosphere, often supplemented by magnetometers measuring the local Earth's magnetic field or satellites performing similar measurements. All Sky Imagers, taking pictures of the night sky and capturing aurora in regular intervals, can for example, be found in Ny-Ålesund and Longyearbyen