SDO | AIA Initial Data

A brief background on AIA:
The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) is designed to provide an unprecedented view of the solar corona, taking images that span at least 1.3 solar diameters in multiple wavelengths nearly simultaneously, at a resolution of ~ 1.2 arcsec and at a cadence of 10 s. The primary goal of the AIA Science Investigation is to use these data, together with data from other SDO instruments and from other observatories, to significantly improve our understanding of the physics behind the activity displayed by the Sun's atmosphere, which drives space weather in the heliosphere and in planetary environments. The AIA will produce data required for quantitative studies of the evolving coronal magnetic field, and the plasma that it holds, both in quiescent phases and during flares and eruptions; the AIA science investigation aims to utilize these data in a comprehensive research program to provide new understanding of the observed processes and, ultimately, to guide development of advanced forecasting tools needed by the user community of the Living With a Star (LWS) program.


Solar activity is driven by the evolving magnetic field. Although the coronal magnetic field cannot be measured directly, much of the magnetic field within a few times 105 km from the surface contains hot plasma that is dense enough to emit detectable levels of light. This plasma is (mostly) frozen onto the field lines, so that the emission from (or absorption by) the plasma outlines the magnetic field. The coronal plasma has a wide range of temperatures, emitting brightest at EUV and soft X-ray wavelengths. The brightness of that emission is a combination of local temperature and density, both of which exhibit very large contrasts with steep gradients perpendicular to the magnetic field. The contrasts in temperature and density exist down to the current best resolution of ~ 1.2 arcsec. A suitably designed imager with narrow thermal responses, such as the AIA, can use these contrasts to dissect the corona into complementary sets of high-contrast images for further analysis.


The AIA is designed to provide, for the first time, multiple near-simultaneous, high-resolution images of the corona covering a wide and continuous temperature range, with the aim to resolve the fundamental observational ambiguity between magnetic field evolution (evidenced by moving loops) and thermal and density changes in adjacent loop atmospheres that outline the magnetic field. To achieve this goal, the AIA images as much of the emitting coronal plasma as is feasible subject to physical and fiscal constraints, by providing the required
1. global coverage of the solar corona, with
2. observations at a wide and continuous range of temperatures,
3. at a cadence that enables the study of impulsive and explosive phenomena, with
4. adequate continuity to study gradual phenomena on time scales up to several weeks.
Achieving the primary investigation goal of understanding the physics of the solar atmosphere requires that the AIA science investigation focus on the evolution of the observed plasma and inferred magnetic field through quantitative analyses of the observations and comparisons with models .