Cloud modeling of a network region in H alpha

Abstract

In this paper, we analyze the physical properties of dark mottles in the chromospheric network using two-dimensional spectroscopic observations in Ha obtained with the Gottingen Fabry-Perot Spectrometer in the Vacuum Tower Telescope at the Observatory del Teide, Tenerife. Cloud modeling was applied to measure the mottles' optical thickness, source function, Doppler width, and line-of-sight velocity. Using these measurements, the number density of hydrogen atoms in levels 1 and 2, total particle density, electron density, temperature, gas pressure, and mass density parameters were determined with the method of Tsiropoula & Schmieder (1997). We also analyzed the temporal behaviour of a mottle using cloud parameters. Our result shows that it is dominated by 3 minute signals in source function, and 5 minutes or more in velocity. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim