Přednášky a semináře

Abstract: During the last decades, several studies had focused on the determination of the prominence temperatures. However, practically all of them were based on the analysis of mainly optical spectral line shapes which brings several difficulties and uncertainties, namely in cases when the spectral lines are optically thick. At the same time, the need for a reliable determination of the temperature in central coolest parts of quiescent prominences has grown as a result of new modeling efforts trying to understand the energy-balance conditions. Using the microwave spectra with a high spatial resolution offers the new possibility. We demonstrate that the fine structures in solar quiescent prominences can be well detected with the ALMA interferometer (Atacama Large Millimeter Array in Chile, joint project of ESO, USA and Japan). ALMA is going to be fully operational and a special hardware setup will allow soon the solar observations. We simulate the visibility of prominence fine structures, their brightness temperatures at various wavelengths and demonstrate the feasibility and usefulness of ALMA observations of solar prominences. Our basic approach is the conversion of high-resolution H-alpha coronagraphic images into the microwave spectral images. Finally, we apply the ALMA image-processing software CASA to our simulated images to see what the ALMA would detect in reality. We discuss various ways how to determine the prominence kinetic temperature from ALMA spectral images.