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Title: Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Abstract

The polarization characteristics of zebra patterns (ZPs) in type IV solar bursts were studied. We analyzed 21 ZP events observed by the Assembly of Metric-band Aperture Telescope and Real-time Analysis System between 2010 and 2015 and identified the following characteristics: a degree of circular polarization (DCP) in the range of 0%–70%, a temporal delay of 0–70 ms between the two circularly polarized components (i.e., the right- and left-handed components), and dominant ordinary-mode emission in about 81% of the events. For most events, the relation between the dominant and delayed components could be interpreted in the framework of fundamental plasma emission and depolarization during propagation, though the values of DCP and delay were distributed across wide ranges. Furthermore, it was found that the DCP and delay were positively correlated (rank correlation coefficient R = 0.62). As a possible interpretation of this relationship, we considered a model based on depolarization due to reflections at sharp density boundaries assuming fundamental plasma emission. The model calculations of depolarization including multiple reflections and group delay during propagation in the inhomogeneous corona showed that the DCP and delay decreased as the number of reflections increased, which is consistent with the observational results. The dispersive polarization characteristicsmore » could be explained by the different numbers of reflections causing depolarization.« less

Authors:
; ; ;  [1];  [2];  [3];  [4]
  1. Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan)
  2. National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo 184-8795 (Japan)
  3. Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan)
  4. Institute for Space—Earth Environmental Research, Nagoya University, Nagoya, Aichi 464-8601 (Japan)
Publication Date:
OSTI Identifier:
22663509
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 842; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRELATIONS; DENSITY; DEPOLARIZATION; EMISSION; PLASMA; POLARIZATION; REFLECTION; SOLAR RADIO BURSTS; SUN; TELESCOPES

Citation Formats

Kaneda, K., Misawa, H., Tsuchiya, F., Obara, T., Iwai, K., Katoh, Y., and Masuda, S., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp. Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA74C1.
Kaneda, K., Misawa, H., Tsuchiya, F., Obara, T., Iwai, K., Katoh, Y., & Masuda, S., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp. Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts. United States. doi:10.3847/1538-4357/AA74C1.
Kaneda, K., Misawa, H., Tsuchiya, F., Obara, T., Iwai, K., Katoh, Y., and Masuda, S., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp. Sat . "Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts". United States. doi:10.3847/1538-4357/AA74C1.
@article{osti_22663509,
title = {Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts},
author = {Kaneda, K. and Misawa, H. and Tsuchiya, F. and Obara, T. and Iwai, K. and Katoh, Y. and Masuda, S., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp},
abstractNote = {The polarization characteristics of zebra patterns (ZPs) in type IV solar bursts were studied. We analyzed 21 ZP events observed by the Assembly of Metric-band Aperture Telescope and Real-time Analysis System between 2010 and 2015 and identified the following characteristics: a degree of circular polarization (DCP) in the range of 0%–70%, a temporal delay of 0–70 ms between the two circularly polarized components (i.e., the right- and left-handed components), and dominant ordinary-mode emission in about 81% of the events. For most events, the relation between the dominant and delayed components could be interpreted in the framework of fundamental plasma emission and depolarization during propagation, though the values of DCP and delay were distributed across wide ranges. Furthermore, it was found that the DCP and delay were positively correlated (rank correlation coefficient R = 0.62). As a possible interpretation of this relationship, we considered a model based on depolarization due to reflections at sharp density boundaries assuming fundamental plasma emission. The model calculations of depolarization including multiple reflections and group delay during propagation in the inhomogeneous corona showed that the DCP and delay decreased as the number of reflections increased, which is consistent with the observational results. The dispersive polarization characteristics could be explained by the different numbers of reflections causing depolarization.},
doi = {10.3847/1538-4357/AA74C1},
journal = {Astrophysical Journal},
number = 1,
volume = 842,
place = {United States},
year = {Sat Jun 10 00:00:00 EDT 2017},
month = {Sat Jun 10 00:00:00 EDT 2017}
}