Turning Noise Into Data: Characterization of the Van Allen Radiation Belt Using SDO Spikes Data

Abstract

The Solar Dynamics Observatory (SDO) is a solar mission in an inclined geosynchronous orbit. Since commissioning, images acquired by Atmospheric Imaging Assembly (AIA) instrument on-board the SDO have frequently displayed “spikes,” pixel regions yielding extreme number of digital counts. These are theorized to occur from energetic electron collisions with the instrument detector system. These spikes are regularly removed from AIA Level 1.0 images to produce clean and reliable data. A study of historical data has found over 100 trillion spikes in the past decade. This project correlates spike detection frequency with radiation environment parameters in order to generate an augmented data product from SDO. We conduct a correlation study between SDO/AIA data and radiation belt activity within the SDO’s orbit. By extracting radiation “spike” data from the SDO/AIA images, we produce a comprehensive data product which is correlated not only with geomagnetic parameters such as Kp, Ap, and Sym-H but also with the electron and proton fluxes measured by the GOES-14 satellite. As a result, we find that AIA spikes are highly correlated with the GOES-14 electrons detected by the magnetospheric electron detector and energetic proton, electron and alpha detectors instruments at the equator (where the two satellites meet) with Spearman’s Correlation values of ρ = 0.73 and ρ = 0.53, respectively, while a weaker correlation of ρ = 0.47 is shown with magnetospheric proton detector protons for the 2 year period where both missions returned data uninterruptedly. This correlation proves that the SDO spike data can be proven useful for characterizing the Van Allen radiation belt, especially at areas where other satellites cannot.Plain Language SummaryThe Solar Dynamics Observatory (SDO) is a NASA mission that has been observing the Sun since 2010. One instrument aboard SDO is the Atmospheric Imaging Assembly (AIA) which acquires pictures of the Sun in seven extreme ultraviolet and two ultraviolet channels. The AIA detector is designed to capture solar photons of different wavelengths to create images. However, SDO is located in a geosynchronous orbit, which passes through regions of the outer radiation belt. Energetic particles that impact the detector result in brightened pixels in the SDO images. An algorithm removes and records these unusual pixels in every AIA image. Although these pixels are considered noise, in this research we use them to infer the particle density along SDO’s orbit. This paper proves that the fluctuation of the number of noisy pixels in AIA’s images best matches the fluctuation of the electron readings from the nearby GOES-14 weather satellite. This research shows that these noisy pixels can be turned to a data product useful for characterizing the Van Allen radiation belt.Key PointsMore than 3 trillion “spiked pixels” attributed to magnetospheric particle impacts have been removed from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images so farThe SDO spike rate was compared to particle measurements from GOES-14 during close orbital conjunctions occurring twice daily over 27 monthsThe high correlation between AIA spikes and GOES-14 electron fluxes indicates that AIA spikes could be a proxy for radiation belt electron fluxes