First Results on Coronal Loop Analysis with AIA/SDO

A decisive question with regard to coronal heating is whether the cross-sectional structure of coronal loops is isothermal or multi-thermal. If the cross-section of an observed coronal loop has an isothermal structure, this indicates macroscopically resolved heating mechanisms, such as chromospheric heating by a flare-like process that channels upflow of heated plasma through the diverging canopy geometry in the transition region and fills coronal fluxtubes with diameters corresponding to the separation of photospheric magneto-convection cells, observed as granulation with spatial scales of about 1000 km. Such diameters of coronal fluxtubes can be resolved with AIA/SDO. On the other side, if the observed loop cross-sections have a multi-thermal structure, this could indicate a substructure with unresolved loop strands with different temperatures, as they would be produced by theoretical nanoflare heating scenarios. Using the 6 coronal filters of AIA/SDO we model the differential emission measure distribution of the smallest resolved coronal loops in active region NOAA 11089, observed on 2010 July 24. We present the first results of DEM modeling that reveals statistics of iso-thermal and multi-thermal loops and their dependence on other physical parameters (temperature, density, loop widths). We discuss the consequences for coronal heating theories.