In recent VLA - Yohkoh (SXT) observations of quiet sun regions with high (several arcs) resolution in the shortest microwave band (at lambda = 1.3, 2.0 and 3.6 cm) were measured brightness contrasts above magnetic network (Benz et al., 1996). Model simulations of observed contrasts with current optical reference atmospheres (FAL, 1993) were inconclusive. We use here the technique of multy frequency tomography (Bogod and Grebinskij, 1997) in a wide range mm - cm band microwave brightness observations for a quiet sun, plages and spots regions, but with middle spatial resolution. Metsahovi observations at shortest microwave band at lambda = 0.34, 0.39, 0.82, 1.35 and 2.59 cm (Urpo et al, 1987) together with RATAN-600 observations at cm waves lambda = 1.8 - 30 cm gives a strong additional restrictions to atmosphere model simulations from deep chromosphere to corona. We discuss the results of such simulations, which leads to some common features of microwave emissitivity of solar atmosphere at different scales of spatial average. We show, that main contribution to microwave brightness gives an optically thin hot plasma (with coronal temperatures), and the chromosphere temperatures plasma, without transitional temperature contribution. Such models, with a power-law temperature distribution in chromosphere, gives good fit with observations at all microwaves range at lambda = 0.3 - 30 cm. We use these results for study of polarization radiation transfer in solar atmosphere and discuss observational results with Nobeyama radio heliograph images of AR 7877 on June 1995 both in intensity and polarization. This work is supported by INTAS Grant No.95-0316 and partially by RFBR Grants No. 96-02-16598, 96-02-16268.
CESRA Workshop on Coronal Explosive Events
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