Frequency Dependence of Polarization of Zebra Pattern in Type-Iv Solar Radio Bursts

Kaneda, Kazutaka; Misawa, Hiroaki; Iwai, Kazumasa; Tsuchiya, F.; Obara, Takao

doi:10.1088/2041-8205/808/2/l45

Cited by 11 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…See Kaneda et al (2015) for a discussion of the frequency dependences of the polarization characteristics of a ZP event.…”

Section: Overview Of the Resultsmentioning

confidence: 99%

“…Melrose (2006) also considered depolarization due to reflection at sharp density boundaries. Kaneda et al (2015) investigated the circumstances under which such depolarization processes occur by analyzing the frequency dependence of the delay between the two circularly polarized components. Based on their results, they suggested that depolarization occurs very close to the emission source, where the difference between the group velocities of the two circular wave modes is relatively large.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Kaneda

Misawa

Iwai

et al. 2017

ApJ

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…See Kaneda et al (2015) for a discussion of the frequency dependences of the polarization characteristics of a ZP event.…”

Section: Overview Of the Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Kaneda

Misawa

Iwai

et al. 2017

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…Likewise, we did not consider the possible evolution of the ZP emission polarisation (e.g. Zlotnik et al 2014;Kaneda et al 2015). Accounting for these effects may provide us with additional seismological information, and hence should be addressed in future studies.…”

Section: Discussionmentioning

confidence: 99%

Effect of a Sausage Oscillation on Radio Zebra-Pattern Structures in a Solar Flare

Nakariakov

Yan

2016

ApJ

View full text Add to dashboard Cite

Sausage modes that are axisymmetric fast magnetoacoustic oscillations of solar coronal loops are characterized by variation of the plasma density and magnetic field, and hence cause time variations of the electron plasma frequency and cyclotron frequency. The latter parameters determine the condition for the double plasma resonance (DPR), which is responsible for the appearance of zebra-pattern (ZP) structures in time spectra of solar type IV radio bursts. We perform numerical simulations of standing and propagating sausage oscillations in a coronal loop modeled as a straight, field-aligned plasma slab, and determine the time variation of the DPR layer locations. Instant values of the plasma density and magnetic field at the DPR layers allowed us to construct skeletons of the time variation of ZP stripes in radio spectra.In the presence of a sausage oscillation, the ZP structures are shown to have characteristic wiggles with the time period prescribed by the sausage oscillation. Standing and propagating sausage oscillations are found to have different signatures in ZP patterns. We conclude that ZP wiggles can be used for the detection of short-period sausage oscillations and the exploitation of their seismological potential.

show abstract

“…On the other hand, there was a strong correlation between the growth rate and peak flux of the bursts. Kaneda et al (2015) investigated the polarization characteristics of a zebra pattern in a type-IV solar radio burst observed with AMATERAS. Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 5070 ms relative to the right-handed component over the entire frequency range of the zebra pattern.…”

Section: Division E Commission 49mentioning

confidence: 99%

“…Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 5070 ms relative to the right-handed component over the entire frequency range of the zebra pattern. Katoh et al (2014) investigated the fine spectral structures included in a type IV burst observed by AMATERAS, and proposed a generation model that suggests wave-wave coupling between Langmuir waves and whistler-mode chorus emissions generated in a post-flare loop. This was inferred from the similarities in the plasma environments of a post-flare loop and the equatorial region of Earth's inner magnetosphere.…”

Section: Division E Commission 49mentioning

confidence: 99%

Division E Commission 49: Interplanetary Plasma and Heliosphere

Mann¹,

Manoharan²,

Gopalswamy³

et al. 2015

Proc. IAU

View full text Add to dashboard Cite

Abstract. After a little more than forty years of work related to the interplanetary plasma and the heliosphere the IAU's Commission 49 was formally discontinued in 2015. The commission started its work when the first spacecraft were launched to measure the solar wind in-situ away from Earth orbit, both inward and outward from 1 AU. It now hands over its activities to a new commission during an era of space research when Voyager 1 measures in-situ the parameters of the local interstellar medium at the edge of the heliosphere. The commission will be succeeded by C.E3 with a similar area of responsibility but with more focused specific tasks that the community intends to address during the coming several years. This report includes a short description of the motivation for this commission and of the historical context. It then describes work from 2012 to 2015 during the present solar cycle 24 that has been the weakest in the space era so far. It gave rise to a large number of studies on solar energetic particles and cosmic rays. Other studies addressed e.g. the variation of the solar wind structure and energetic particle fluxes on long time scales, the detection of dust in the solar wind and the Voyager measurements at the edge of the heliosphere. The research is based on measurements from spacecraft that are at present operational and motivated by the upcoming Solar Probe + and Solar Orbiter missions to explore the vicinity of the Sun. We also report here the progress on new and planned radio instruments and their importance for heliospheric studies. Contributors to this report are

show abstract

Frequency Dependence of Polarization of Zebra Pattern in Type-Iv Solar Radio Bursts

Cited by 11 publications

References 20 publications

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Polarization Characteristics of Zebra Patterns in Type IV Solar Radio Bursts

Effect of a Sausage Oscillation on Radio Zebra-Pattern Structures in a Solar Flare

Division E Commission 49: Interplanetary Plasma and Heliosphere

Contact Info

Product

Resources

About