The distribution of temperature perturbations over the solar photosphere was reconstructed. The k–ω and phase filtering was applied to Fourier image of space–time variations of temperature in order to find the signatures of local internal gravity waves. Within the convectively stable photospheric layers, the structures have been identified featuring the following properties: quasi‐periodicity in space (at scales of mesogranulation) and time, mostly horizontal propagation with subsonic velocities, the group velocity of and the wavepacket perpendicular to its phase velocity. Such properties are exactly those of internal gravity waves.

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In this paper, the physical conditions within the inhomogeneous solar atmosphere have been reconstructed by means of solving the inverse problem of non‐local thermodynamic equilibrium (NLTE) radiative transfer. The profiles of the λ= 523.42 nm Fe i spectral line of high spatial and time resolution were used as observational data. The velocity field has been studied for the real solar granulation in the superadiabatic layer and overshooting convection region. Also, we investigate the vertical structure of the inhomogeneous solar photosphere and consider the penetration of granules from the convective region into the upper layers of the stable atmosphere. The microturbulent velocity appears to be minimal at the bottom of the overshooting convection region and increases sharply through the superadiabatic layer and upper photosphere. High‐turbulence layers emerge either in the central part of a flow or at the boundary of an incipient flow with subsequent drift towards the centre of the flow. Wide descending flows tend to disintegrate into structures having turbulence augmented and these structures correspond to the flows of matter. High microturbulence of the intensive flows provokes steep temperature depression in the upper photosphere leading to the second inversion of temperature for the intergranules. The inversion of vertical velocities is observed to be frequent in the solar granulation. Some of the convective flows reach the minimum temperature region. Vertical convective velocities of the matter flows are found to be smaller in the middle and upper photosphere. Also, the effect of finite resolution on spatial variations of the velocities in the solar photosphere has been estimated.

We present a study of the pre-peak phase of the solar flare of M6.4 / 3N class which arose on July 19, 2000 in the NOAA 9087 active region. The effective magnetic field Beff was measured using the FeI 6301.5 Ǻ, FeI 6302.5 Ǻ, Hα and Hβ spectral lines. It was found that at the brightest place of the flare, which was projected onto a small sunspot of N polarity, Beff was close to each other on all four lines and corresponded to 1.0-1.2 kG. At the same time, the modulus of the magnetic field at the level of FeI 6302.5 formation, determined by the splitting of peaks V of the Stokes parameter and the localization of the σ-components in the I ± V profiles, was in the range 1.6–2.6 kG. The bisectors of the I + V and I – V profiles of the FeI 6301.5 line are parallel to each other, indicating a simple one-component structure of the magnetic field at the level of the middle photosphere under the flare. The Balmer decrement of Imax (Hα) / Imax (Hβ) by Hα and Hβ lines was 1.16. The semi-empirical model of the photospheric layers of the flare was constructed using Stokes I observations of non-magneticsensitive FeI 5123.7 and 5434.5 lines by solving the inverse equilibrium transfer problem using Tikhonov stabilizers. For the distribution of temperature with height, the effects of deviation from the LTE were found to be significant for the layers of the lower photosphere corresponding to the heights h ≥ 0 (i.e. τ 5 ≤ 1). In the entire thickness of the photosphere (h = 0–500 km), the flare temperature is lower compared to the non-perturbed atmosphere, while it is slightly higher for h> 500 km. The micro-turbulent velocity is increased at altitudes h> 200–500 km, while at altitudes h <200 km it is reduced. The obtained results indicate that the upper photosphere and the lower chromosphere are perturbed during solar flares, even when the magnetic field is quasi-homogeneous in the lower layers (middle photosphere).

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