MICROWAVE INDICATOR OF POTENTIAL GEOEFFECTIVENESS AND MAGNETIC FLUX-ROPE STRUCTURE OF A SOLAR ACTIVE REGION

• Main Authors: A.V. Kudriavtseva, I.I. Myshyakov, A.M. Uralov, V.V. Grechnev
• Format: Article
• Language: English
• Published: INFRA-M 2021-03-01
• Series: Solar-Terrestrial Physics
• Subjects: solar active regions; magnetic fields; microwave emission; solar flare forecast
• Online Access: https://naukaru.ru/en/nauka/article/39667/view

We analyze the presence of a microwave neutral-line-associated source (NLS) in a super-active region NOAA 12673, which produced a number of geo-effective events in September 2017. To estimate the NLS position, we use data from the Siberian Radioheliograph in a range 4–8 GHz and from the Nobeyama Radioheliograph at 17 GHz. Calculation of the coronal magnetic field in a non-linear force-free approximation has revealed an extended structure consisting of interconnected magnetic flux ropes, located practically along the entire length of the main polarity separation line of the photospheric magnetic field. NLS is projected into the region of the strongest horizontal magnetic field, where the main energy of this structure is concentrated. During each X-class flare, the active region lost magnetic helicity and became a CME source.