Millimeter emission of solar flares

Eclipse on the Coral Sea: Cycle 24 Ascending

物理学;天文学

Nagnibeda, V.G.^1 ; Smirnova, V.V.^1,2 ; Ryzhov, V.S.^3 ; Zhiltsov, A.V.^3

Sobolev Astronomical Institute, Saint Petersburg State University, Universitetsky pr.28, St. Petergof, 198504, Russia^1

Central (Pulkovo) Astronomical Observatory, Russian Academy of Sciences, Pulkovskoe shausse 65, St.Petersburg, 196140, Russia^2

Bauman Moscow State Technical University, 2 Bauman street 5, Moscow, 105005, Russia^3

关键词: Bauman moscow state technical universities;    Emission enhancement;    Emission mechanism;    Energetic electron;    High energetic electrons;    Microwave observations;    Space-based observations;    Temporal structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/440/1/012009/pdf
DOI  :  10.1088/1742-6596/440/1/012009

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

We analyzed two unique radio observations of millimeter solar flares at 93 and 140 GHz with the THz component in these spectra. Data were obtained from ground-based radio-telescope RT-7.5 operated by Bauman Moscow State Technical University (BMSTU) with the spacial resolution of 2.5 and 1.5 arc-minutes. We analyzed temporal structure of observed radio-bursts and their dynamics in comparison with soft and hard X-ray light-curves obtained from GOES and RHESSI space-based observations. It was found the 140 GHz emission enhancement at the spectra that is new independent confirmation of the THz component existance. Also, we analyzed data of microwave solar flares with the emission enhanced at 35 GHz obtained from Nobeyama radioheliograph (NoRH) and radiopolarimeter (NoRP). It was found that the maximum of the flux density spectra was shifted toward high frequencies that didn't agree with the model spectrum obtained from microwave observations. We assumed, that such kind of spectra are associated with the gyro-synchrotron radiation of the significant number of high-energetic electrons emission with energies of about 500 keV. The emission mechanism at millimeter waves is the gyro-synchrotron radiation. However, if the energetic electrons are not enough the thermal emission mechanism could be dominant factor at millimeter radiation that could also explain the spectral maximum shift to high frequencies.