Current-sheet-associated radio sources and development of the magnetosphere of an active region revealed from 17 GHz and Yohkoh data

摘要: We study the evolution of active region (AR) NOAA 7321 in which appeared a so-called `neutral-line-associated source' (NLS) on basis data Nobeyama Radioheliograph and Yohkoh/SXT. provide physical interpretation NLS terms topological magnetic reconnection model quadrupole configuration discuss its relation to region. Two kinds were observed at 17 GHz. One them, `rising NLS', was found growth stage. The other `stationary NLS' detected maximal stage AR. Their presence associated with substantial expansion region's magnetosphere accompanied by gradual development spine-like structures visible soft X-rays before homologous long-duration arcade flares. suggest that rising GHz corresponded fragment `horizontal' current sheet moving upward. Bright X-ray spines boundaries sheet. Almost all bursts from 26 28 October 1992 class C M flares occurred NLS. Formation X-point singularities is believed be responsible for low-lying Reversal circular polarization due effect radio wave propagation limb. initial microwave burst X9 flare 2 November this also revealed observational manifestations `vertical' non-neutral spatial structure flare.