High resolution coronal imaging with multilayers Original Research Article

Since the 1960s, when on-disk coronal imaging became possible, progress in the field has consisted largely in improving the spectral spatial and temporal resolution of the observations. With the development of normal-incidence, soft X-ray and XUV multilayer optics in the 1980s, a dramatic improvement in the first two of these occurred, and with the development of better detectors the temporal resolution (along with the sensitivity) also improved. In this paper we discuss recent results from The Transition Region and Coronal Explorer (TRACE), which is providing observations of the solar outer atmosphere with unprecedented spatial and temporal resolution. The new views of coronal structure and dynamics being obtained indicate that: (i) the corona is filled with flows of both hot and cool material, (ii) instead of “loops,” the basic coronal structures are threads, and (iii) threads of hot plasma appear to form as parallel bundles on surfaces, which may correspond to dissipation at quasi-separatrix layers. We conclude with a discussion of the possible next generation of high resolution missions.