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Title: Observation of a metric type N solar radio burst

Journal Article · · The Astrophysical Journal (Online)
ORCiD logo [1];  [1];  [1];  [1];  [1]; ORCiD logo [2];  [1];  [1]; ORCiD logo [3];  [4]
  1. Shandong Univ., Shandong (China)
  2. Shandong Univ., Shandong (China); National Academy of Sciences of Ukraine, Kharkiv (Ukraine)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Univ. of Alabama, Huntsville, AL (United States)
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Type III and type-III-like radio bursts are produced by energetic electron beams guided along coronal magnetic fields. As a variant of type III bursts, Type N bursts appear as the letter "N" in the radio dynamic spectrum and reveal a magnetic mirror effect in coronal loops. Here, we report a well-observed N-shaped burst consisting of three successive branches at metric wavelength with both fundamental and harmonic components and a high brightness temperature (>109 K). We verify the burst as a true type N burst generated by the same electron beam from three aspects of the data. First, durations of the three branches at a given frequency increase gradually and may be due to the dispersion of the beam along its path. Second, the flare site, as the only possible source of non-thermal electrons, is near the western feet of large-scale closed loops. Third, the first branch and the following two branches are localized at different legs of the loops with opposite senses of polarization. We also find that the sense of polarization of the radio burst is in contradiction to the O-mode and there exists a fairly large time delay (~3–5 s) between the fundamental and harmonic components. Possible explanations accounting for these observations are presented. Finally, assuming the classical plasma emission mechanism, we can infer coronal parameters such as electron density and magnetic field near the radio source and make diagnostics on the magnetic mirror process.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC52-06NA25396
OSTI ID:
1343706
Report Number(s):
LA-UR-16-24317; TRN: US1701548
Journal Information:
The Astrophysical Journal (Online), Vol. 830, Issue 1; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 8 works
Citation information provided by
Web of Science

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Cited By (2)

Harmonics of Solar Radio Spikes at Metric Wavelengths journal February 2018
The Low-Frequency Solar Corona in Circular Polarization journal August 2019

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Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
astronomy and astrophysics
sun: corona
sun: flares
sun: magnetic fields
sun: radio radiation