Spectral manifestations of the spatial structure and dynamic processes of chromospheric flares on the Sun

The nature of spectrographic manifestations of ascending elongated and point arc patterns with descending plasma flows is discussed. A conclusion is drawn regarding the relation between the rate of ascent of the arc and the velocities of the directional motion of the radiating plasma in the same arc. Qualitative agreement of the calculated profiles of spectral lines of the point arc patterns with the line profiles of Severnyj's ''whiskers'' was obtained. The elongated arc patterns appear in the spectrum in form of characteristic emission ''peaks'', analogous to those observed in flares in the H and K CaII lines. One of their important peculiarities is the existence of bright compact nodes. Only in these nodes do we observe flare glow in the hydrogen and metal lines. The obtained results elucidate the nature of the origin of ''flare nodes'', of ''emission peaks'' in the H and K CaII lines and also indicate the necessity for photometric investigations of flares, taking into account their actual spatial structure. (author)