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P: Fachverband Plasmaphysik
P 3: Plasma Wall Interactions I / Astrophysical Plasmas
P 3.6: Vortrag
Montag, 5. März 2018, 15:15–15:30, A 0.112
Optical spectroscopy of coronal iron in an electron beam ion trap — •Hendrik Bekker, Christian Hensel, Arnesh Daniel, Alexander Windberger, and José R. Crespo López-Urrutia — Max-Planck-Insitüt für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg
Solar eclipses, such as the recent (August 21st 2017) all-American total eclipse, are prime opportunities to study the weak optical coronal emission. This is because normally, emission from the photosphere overpowers it. Known since the 1870s, and first explained in the 1930s, the forbidden lines of highly charged iron ions are still a visible reminder of the not-yet well understood coronal heating mechanisms. This is in part due to a lack of reference data of the studied transitions. Therefore, we have investigated the optical spectra of highly charged Fe X-XIV ions using the Heidelberg electron beam ion trap (HD-EBIT). Using grating spectrometers, 12 lines were studied. Wavelengths of the often observed red and green coronal lines were determined with better-than-ppm precision, allowing in principle for absolute velocity determinations in coronal plasmas with uncertainties below 0.2 km s−1. Furthermore, the Zeeman splitting of several of the lines in the strong magnetic field of the HD-EBIT was measured, yielding data of interest for studying the influence of magnetic fields in the coronal heating problem.