Fig 2 - uploaded by P. Schwartz
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Absorption and coronal emissivity deficit at a prominence and coronal emissivity deficit alone in the cavity cause decrease of the coronal intensity. I p is the coronal intensity measured at a prominence, I c in the surrounding cavity, and I c in the adjacent quiet corona. The intensities of radiation emitted by the corona in front of and behind the prominence are denoted I f and I b , respectively (Heinzel et al. 2008).
Source publication
The mass of selected prominences was estimated using their multi-wavelength
observations: in Hα by the HSFA2 spectrograph of the Ondřejov
observatory, in EUV by SoHO/EIT and in the soft X-rays by Hinode XRT.
The results are compared with values estimated by other authors.
Context in source publication
Context 1
... order to elimi- nate the effect of the coronal emissivity deficit on the decrease of the EUV coronal intensities. As the calculation of the optical thickness along a cut made across a prominence tangentially to the limb has already been explained in Heinzel et al. (2008), we give here only a brief description of the method. As it can be seen in Fig. 2, the coronal intensities I c , both in EUV and X-ray spectral regions, are lower than I c measured in the corona due to reduced coronal emission in a low-density cavity. Assuming that the prominence plasma is composed mainly of hydrogen and helium and the X-ray coronal radiation is not absorbed in the prominence ( Anzer et al. 2007), ...
Citations
... In contrast to determining spatial and dynamic characteristics, estimation of the mass and, consequently, the gravitational energy of prominences proves to be a much more difficult task. The most precise methods developed so far are generally based on measuring the fraction of background radiation absorbed by a prominence, most commonly in the iron EUV lines (Gilbert, Holzer, and MacQueen, 2005;Schwartz et al., 2012). Unfortunately, this approach can be only used in a limited number of cases, when prominences are observed against a sufficiently uniform background, which does not change much over time. ...
We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304 A line taken close to the solar minimum of 2008-2009 and focus mainly on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25x25 to 150x500 Mm in size and obtain
distributions of many their spatial characteristics, such as latitudinal position, height, size and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to be rarely exceeding 3 km/s. Besides, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to evaluate the total mass and gravitational energy of all simultaneously existing prominences (10e12-10e14 kg and 10e29-10e31 erg, respectively). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive it to be a power-law of index -1.1 +- 0.2.
