A Compact Spectral Range and Matching Extreme-Ultraviolet Spectrometer for the Simultaneous Study of 1 × 104-2 × 107 K Solar Plasmas

摘要

An EUV spectral range of less than 100 ? in first order has been found that includes sufficient spectral lines and critical combinations of lines in first and second order to permit dynamic and diagnostic investigations of the solar atmosphere with a relatively simple spectrometer. An optical design of such a spectrometer, based on the performance of the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) spacecraft, and sample stigmatic solar spectra for the range 1334-1428 ? from SUMER are presented to illustrate the utility of this range. Lines of almost all abundant solar elements except H and He are present within this wavelength band in first or second order. The lines cover the large temperature range from 1 × 104 K (chromosphere) to 2 × 107 K (flares). The spectrometer's resolution is sufficiently high to permit measuring line profiles and wavelength shifts which allows plasma dynamical studies of individual solar structures from the chromosphere up into the corona. In addition, electron density diagnostics are available within the spectral range that cover the temperature range from 8 × 104 to 1 × 106 K and an electron density range from 108 to 1013 cm-3.