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Title: Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare

Abstract

The radiation of microwave sources above sunspots at a frequency of 17 GHz gives information about the parameters of solar plasma in the regions where the magneti-field strength is B ~ 2000 G in the transition region between the chromosphere and corona. Short-period oscillations (with a period of several minutes) of microwave emission from solar active regions (ARs) reflect wave processes in magnetic flux tubes of sunspots. Short-period oscillations of microwave emission from AR NOAA 12242 before two flares on December 17, 2014 are analyzed. This analysis is based on solar radio images obtained by means of the Nobeyama Radio Heliograph with a 10″−15″ two-dimensional spatial resolution. The radio maps of the whole solar disk were synthesized in a nonstandard mode with a cadence of 10 s and an averaging time of 10 s. An increase in the power of about ten-minute oscillations of microwave radiation approximately 40 to 50 min before the M1.5 flare (01: 00 UT) is found. On the same day, an increase in the power of ten-minute oscillations is observed about 60 min before the M8.7 flare (04: 42 UT). This effect is similar to the effect found earlier by two groups of authors independently formore » three-minute oscillations—namely, they observed a sharp increase in three-minute oscillations 15 to 20 min before the radio burst accompanying the flare. The effect in question may be interpreted as an relationship ofMHD waves propagating along the magnetic flux tube of a sunspot and the onset of the solar flare.« less

Authors:
 [1];  [2]
  1. Russian Academy of Sciences, Central Astronomical Observatory at Pulkovo (Russian Federation)
  2. National Research University Higher School of Economics (Russian Federation)
Publication Date:
OSTI Identifier:
22761725
Resource Type:
Journal Article
Journal Name:
Physics of Atomic Nuclei
Additional Journal Information:
Journal Volume: 81; Journal Issue: 3; Other Information: Copyright (c) 2018 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1063-7788
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CHROMOSPHERE; GHZ RANGE 01-100; IMAGES; MAGNETIC FLUX; MICROWAVE RADIATION; OSCILLATIONS; SOLAR FLARES; SPATIAL RESOLUTION; SUNSPOTS; TUBES; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Abramov-Maximov, V. E., E-mail: beam@gaoran.ru, and Bakunina, I. A., E-mail: rinbak@mail.ru. Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare. United States: N. p., 2018. Web. doi:10.1134/S1063778818030031.
Abramov-Maximov, V. E., E-mail: beam@gaoran.ru, & Bakunina, I. A., E-mail: rinbak@mail.ru. Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare. United States. doi:10.1134/S1063778818030031.
Abramov-Maximov, V. E., E-mail: beam@gaoran.ru, and Bakunina, I. A., E-mail: rinbak@mail.ru. Tue . "Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare". United States. doi:10.1134/S1063778818030031.
@article{osti_22761725,
title = {Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare},
author = {Abramov-Maximov, V. E., E-mail: beam@gaoran.ru and Bakunina, I. A., E-mail: rinbak@mail.ru},
abstractNote = {The radiation of microwave sources above sunspots at a frequency of 17 GHz gives information about the parameters of solar plasma in the regions where the magneti-field strength is B ~ 2000 G in the transition region between the chromosphere and corona. Short-period oscillations (with a period of several minutes) of microwave emission from solar active regions (ARs) reflect wave processes in magnetic flux tubes of sunspots. Short-period oscillations of microwave emission from AR NOAA 12242 before two flares on December 17, 2014 are analyzed. This analysis is based on solar radio images obtained by means of the Nobeyama Radio Heliograph with a 10″−15″ two-dimensional spatial resolution. The radio maps of the whole solar disk were synthesized in a nonstandard mode with a cadence of 10 s and an averaging time of 10 s. An increase in the power of about ten-minute oscillations of microwave radiation approximately 40 to 50 min before the M1.5 flare (01: 00 UT) is found. On the same day, an increase in the power of ten-minute oscillations is observed about 60 min before the M8.7 flare (04: 42 UT). This effect is similar to the effect found earlier by two groups of authors independently for three-minute oscillations—namely, they observed a sharp increase in three-minute oscillations 15 to 20 min before the radio burst accompanying the flare. The effect in question may be interpreted as an relationship ofMHD waves propagating along the magnetic flux tube of a sunspot and the onset of the solar flare.},
doi = {10.1134/S1063778818030031},
journal = {Physics of Atomic Nuclei},
issn = {1063-7788},
number = 3,
volume = 81,
place = {United States},
year = {2018},
month = {5}
}