High-resolution solar imaging with a photon sieve

Dissipation in the solar corona is expected to occur in extremely thin current sheets of order 1-100 km. Emission from these current sheets should be visible in coronal EUV emission lines. However, this spatial scale is far below the resolution of existing imaging instruments, because conventional optics cannot be easily manufactured with sufficient surface figure accuracy to obtain the required < 0.1 arcsec resolution. A photon sieve, a diffractive imaging element, can be manufactured to provide a few 10-3 arcsec resolution, with much more relaxed tolerances than conventional imaging technology. A simple design for a sounding rocket payload is presented that obtain 80 mArcsec imaging with a 100 mm diameter photon sieve to image Fe XIV 334 and Fe XVI 335. These images will not only show the structure of the corona at a resolution never before obtained, they will also allow a study of the temperature structure.