Extreme ultraviolet (EUV) solar spectral irradiance (SSI) for ionospheric application – history and contemporary state-of-art

[摘要] After a historical survey of space related EUV measurements in Germany andthe role of Karl Rawer in pursuing this work, we describe presentdevelopments in EUV spectroscopy and provide a brief outlook on futureactivities. The group of Karl Rawer has performed the first scientific spaceproject in Western Europe on 19th October 1954. Then it was decided toinclude the field of solar EUV spectroscopy in ionospheric investigations.Starting in 1957 an intensified development of instrumentation was going onto explore solar EUV radiation, atmospheric airglow and auroral emissionsuntil the institute had to stop space activities in the earlynineteen-eighties. EUV spectroscopy was continued outside of the instituteduring eight years. This area of work was supported again by the institutedeveloping the Auto-Calibrating Spectrometers (SolACES) for a mission on theInternational Space Station (ISS). After more than six years in space theinstrument is still in operation. Meanwhile the work on the primary taskalso to validate EUV data available from other space missions has made goodprogress. The first results of validating those data and combine them intoone set of EUV solar spectral irradiance are very promising. It will berecommended for using it by the science and application community. Moreover,a new low-cost type of an EUV spectrometer is presented for monitoring thesolar EUV radiation. It shall be further developed for providing EUV-TECdata to be applied in ionospheric models replacing the Covington indexF_10.7. Applying these data for example in the GNSS signal evaluation amore accurate determination of GNSS receiver positions is expected forcorrecting the propagation delays of navigation signals traveling throughthe ionosphere from space to earth. – Latest results in the field of solarEUV spectroscopy are discussed, too.

[学科分类] 电子、光学、磁材料