ИСТИНА

In the past, Mg I lines have been detected in some bright prominences but their study was not systematic. Recently we started a project of monitoring Mg I emission in prominences by using the Ondrejov solar spectrograph. Our preliminary results indicate that the Mg I emission is detectable (with the sensitivity of our instrument) only in prominences which are located close to active or even flaring regions. We show a correlation of the detected Mg I emission with 160 nm SDO/AIA brightness of the solar disk surrounding prominences. We interpret this as the effect of Mg I photoionization in the resonance continuum below 160 nm. These results have relevance to current prominence studies in Mg II lines which are now frequently observed by the IRIS satellite. The radiative-transfer modeling is in progress. http://oh.geof.unizg.hr/images/meetings/XIV-HAC/HAC-XIV-sci-programme.pdf