Spectral characteristics of a rotating solar prominence in multiple wavelengths

Abstract

We present synthetic spectra corresponding to a 2.5D magnetohydrodynamic simulation of a rotating prominence in the Ca II 8542 Å, H α, Ca II K, Mg II k, Ly α, and Ly β lines. The prominence rotation resulted from angular momentum conservation within a flux rope where asymmetric heating imposed a net rotation prior to the thermal-instability-driven condensation phase. The spectra were created using a library built on the Lightweaver framework called Promweaver, which provides boundary conditions for incorporating the limb-darkened irradiation of the solar disk on isolated structures such as prominences. Our spectra show distinctive rotational signatures for the Mg II k, Ly α, and Ly β lines, even in the presence of complex, turbulent solar atmospheric conditions. However, these signals are barely detectable for the Ca II 8542 Å, H α, and Ca II K spectral lines. Most notably, we find only a very faint rotational signal in the H α line, thus reigniting the discussion on the existence of sustained rotation in prominences.