Application of Novel Multilayer Normal-Incidence Mirrors for EUV Solar Spectroscopy

Recent significant progress in the development of multilayer normal-incidence EUV mirrors is primarily related to an increase in the reflection coefficient at the working wavelength, a decrease in the spectral width of the reflection curve, and application of high-efficiency multilayer coatings for short-wavelength (3–9 nm) and long wavelength (greater than 50 nm) spectral ranges. Such mirrors allow astrophysical study of the Sun, since relatively narrow spectral widths of the mirrors and high reflection coefficients make it possible to image corona in monochromatic lines. Telescopes based on the mirrors are promising for dynamic spectral diagnostics of the solar disk with the aid of imaging spectroscopy. The method is based on the detection of monochromatic images of the Sun using the EUV spectral lines with relatively high spatial and temporal resolution. Possible progress in the solar study related to application of specified optical elements is discussed.