Ryohko Ishikawa

TL;DR: In this paper, the magnetic field from the photosphere to the very upper chromosphere of the Sun has been inferred from spectropolarimetric observations of an active region plage and its surrounding enhanced network.

TL;DR: In this paper, the authors present a strategy with which to realize high-precision spectro-polarimetry in the vacuum ultraviolet (VUV) range using the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP).

TL;DR: The proposed VUV spectropolarimeter has two optically symmetric channels to simultaneously measure orthogonal linear polarization states with a single concave diffraction grating that serves both as the spectral dispersion element and beam splitter and to minimize the polarization errors caused by possible time variation of the VUV flux during the polarization modulation and by statistical photon noise.

TL;DR: It is shown that MgF2 can be applied practically as a half-waveplate for the chromospheric Lyman-alpha spectro-polarimeter (CLASP) sounding rocket experiment and that the developed measurement method can be easily applied to other VUV birefringent materials at other wavelengths.

TL;DR: In this paper, three types of high-reflectivity mirror and filter coatings for a solar spectropolarimeter in the hydrogen Lyman-α-v ultraviolet (VUV) region and evaluated their performance.