A Global Survey of EUV Corona Power Spectra

TL;DR

This study conducts a comprehensive analysis of EUV solar corona power spectra using SDO/AIA data, revealing correlations with solar features, oscillations, and magnetic structures, enhancing understanding of solar atmospheric dynamics.

Contribution

It introduces a global survey of EUV corona power spectra with novel spectral modeling, linking spectral features to specific solar phenomena and magnetic regions.

Findings

Spectral parameters directly relate to visible solar features.

Detected multiple quasi-periodic oscillations at 3 and 5 minutes.

Identified unique spectral signatures of coronal holes and filaments.

Abstract

We present results of a global survey of single-pixel intensity power spectra from a 12-hour time period on 26 June 2013 in a 1600x1600 pixel region from four channels of the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) instrument. We extract single-pixel time series from a derotated image sequence, fit models to the power spectra of these time series, and study the spatial dependence of the model parameters. Two power spectra models are considered: i) a three-parameter power-law + tail model and ii) a power-law + tail model + three-parameter localized Lorentzian, the latter to model periodicity. Spectra are well-described by at least one of these models for all pixel locations, with the spatial distribution of best-fit model parameters shown to provide new and unique insights into turbulent, quiescent and periodic features in the EUV corona and upper photosphere. Findings include: individual model parameters correspond clearly and directly to visible solar features; detection of numerous quasi-periodic three- and five-minute oscillations; observational identification of concentrated magnetic flux as regions of largest power-law indices [n]; identification of unique spectral features of coronal holes and filaments; identification of sporadic and pervasive five-minute oscillations throughout the corona; detection of the known global ~4.0-minute chromospheric oscillation; "coronal bullseyes" appearing as radially decaying periodicities over sunspots and sporadic foot-point regions; and "penumbral periodic voids" appearing as broad rings around sunspots in 1600 and 1700 {\AA} in which spectra contain no statistically significant periodic component.