18 citations · 67 across the 6 of their papers we have counts for
6 papers
Velocity difference of ions and neutrals in solar prominences
Eberhard Wiehr, Goetz Stellmacher, Horst Balthasar +1
Marked velocity excesses of ions relative to neutrals are obtained from two time series of the neighboring emission lines He I 5015 and Fe II 5018 in a quiescent prominence. Their…
Evidence for the two fluid scenario in solar prominences
Eberhard Wiehr, Götz Stellmacher, Michele Bianda
This paper presents observational evidence of the different dynamical behavior of neutral and ionized species in solar prominences. The analysis of a time-series of Sr II 4078 A an…
The Na I and Sr II Resonance Lines in Solar Prominences
Goetz Stellmacher, Eberhard Wiehr
We estimate the electron density, n_e, and its spatial variation in quiescent prominences from the observed emission ratio of the resonance lines Na I 5890 (D2) and Sr II 4078. For…
Non-thermal line-broadening in solar prominence
Goetz Stellmacher, Eberhard Wiehr
We show that the line broadening in quiescent solar prominences is mainly due to non-thermal velocities. We have simultaneously observed a wide range of optically thin lines in qui…
The Deep Layers of Sunspot Umbrae
Goetz Stellmacher, Eberhard Wiehr
We model the deepest observable layers of dark sunspot umbral atmospheres in terms of an empirical model which equally describes observed near infrared continuum intensities and li…
Helium Emissions Observed in Ground-Based Spectra of Solar Prominences
Renzo Ramelli, Goetz Stellmacher, Eberhard Wiehr +1
The only prominent line of singly ionized helium in the visible spectral range, helium-II 4686 A, is observed together with the helium-I 5015 A singlet and the helium-I 4471 A trip…