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Figure 1: Schematic diagram showing the atomic model of He I comprising the five lowest bound levels plus continuum. |
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Figure 2: Line profiles of He I 10 830 Å depending on the atmospheric models and the effect of a nonthermal electron beam. From left to right, the three panels refer to three atmospheric models: VAL-C (Vernazza et al. 1981), F1 and F2 (Machado et al. 1980). The solid lines refer to the case without an electron beam, while the dashed and dotted lines refer to the cases with electron beams whose energy fluxes are 109 and 1010 erg cm-2 s-1, respectively. The profiles are computed at solar disk center and normalized to the nearby continuum. |
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Figure 3:
Line source function and optical depth at 10 830.341 Å (the center of the strongest component of
the He I 10 830 Å line) in different atmospheric models and for different cases
of nonthermal electron beams. The quantities of ![]() |
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Figure 4: Transitions to the triplet levels corresponding to the He I 10 830 Å line through three different processes: the photoionization-recombination mechanism (PRM, solid lines), the collisional mechanism (CM, dashed lines), and the collisional ionization-recombination mechanism (CRM, dotted lines). The upper panels show the case without an electron beam, while the lower panels are for the case with an electron beam of energy flux 109 erg cm-2 s-1. |
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