Coronal cavities are regions of low coronal emission that usually sit above solar prominences. These systems can exist for days or months before erupting. The magnetic structure of the prominence-cavity system during the quiescent period is important to understanding the pre-eruption phase. We describe observations of a coronal cavity situated above a solar prominence observed on the western li...

We discuss the stability of a flux tube model for quiescent solar prominences. The main result is that the configurations are stable only up to a critical width (defined as the extension of the central part of the flux tube with prominence matter at low temperatures) of about 1 000 km to 3 000 km. The dependence of the critical width on the prominence parameters height, temperature, density con...

Abstract We analyzed multiline observations of a quiescent prominence from the slit spectrograph located at Ondřejov Observatory. Dopplergrams and integrated intensity maps whole were obtained in six spectral lines: Ca ii H, H ϵ , β He i D3, α IR. By combining with non-LTE radiative-transfer modeling, we carefully identified areas an optically thin regime. The comparison Doppler-velocity scatte...