Multimodal Differential Emission Measure in the Solar Corona

Abstract

The Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamics Observatory (SDO) provides coronal EUV imaging over a broader temperature sensitivity range than the previous generations of instruments (EUVI, EIT, and TRACE). Differential emission measure tomography (DEMT) of the solar corona based on AIA data is presented here for the first time. The main product of DEMT is the three-dimensional (3D) distribution of the local differential emission measure (LDEM). While in previous studies, based on EIT or EUVI data, there were 3 available EUV bands, with a sensitivity range $\sim 0.60-2.70$ MK, the present study is based on the 4 cooler AIA bands (aimed at studying the quiet sun), sensitive to the range $\sim 0.55-3.75$ MK. The AIA filters allow exploration of new parametric LDEM models. Since DEMT is better suited for lower activity periods, we use data from Carrington Rotation 2099, when the Sun was in its most quiescent state during the AIA mission. Also, we validate the parametric LDEM inversion technique by applying it to standard bi-dimensional (2D) differential emission measure (DEM) analysis on sets of simultaneous AIA images, and comparing the results with DEM curves obtained using other methods. Our study reveals a ubiquitous bimodal LDEM distribution in the quiet diffuse corona, which is stronger for denser regions. We argue that the nanoflare heating scenario is less likely to explain these results, and that alternative mechanisms, such as wave dissipation appear better supported by our results.

52 pages, 18 figures

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Cited by in corpus (9)

• The Effect of Solar Wind Expansion and Non-Equilibrium Ionization on the Broadening of Coronal Emission Lines
• The Slowly Varying Corona: I --- Daily Differential Emission Measure Distributions Derived from EVE Spectra
• Thermodynamic Structure of the Solar Corona: Tomographic Reconstructions and MHD Modeling
• SITES: Solar Iterative Temperature Emission Solver for differential emission measure inversion of EUV observations
• Mass Loss Evolution in the EUV Low Corona from SDO/AIA Data
• Signatures of the non-Maxwellian $\kappa$-distributions in optically thin line spectra. II. Synthetic Fe XVII--XVIII X-ray coronal spectra and predictions for the Marshall Grazing-Incidence X-ray Spectrometer (MaGIXS)
• Energy Input Flux in the Global Quiet-Sun Corona
• Enthalpy-based modeling of tomographically reconstructed quiet-Sun coronal loops
• Three-Dimensional Reconstruction and Thermal Modelling of Observed Loops