2015/07/30 by Kazutaka Kaneda, Hiroaki Misawa, Kazumasa Iwai +3 · 1 citation
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Gamma-ray bursts and supernovae #Geomagnetism and Paleomagnetism Studies #Solar and Space Plasma Dynamics #astro-ph.SR
paper · pdf · doi:10.1088/2041-8205/808/2/l45
published as ApJL, 808, L45 (2015) · 20 pages, 5 figures, published in ApJL
openalex publication_date 2015/07/30 · arxiv created 2015/08/11 · arxiv updated 2015/08/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We investigated the polarization characteristics of a zebra pattern (ZP) in a type-IV solar radio burst observed with AMATERAS on 2011 June 21 for the purpose of evaluating the generation processes of ZPs. Analyzing highly resolved spectral and polarization data revealed the frequency dependence of the degree of circular polarization and the delay between two polarized components for the first time. The degree of circular polarization was 50%–70% right-handed and it varied little as a function of frequency. Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 50–70 ms relative to the right-handed component over the entire frequency range of the ZP and this delay increased with the frequency. We examined the obtained polarization characteristics by using pre-existing ZP models and concluded that the ZP was generated by the double-plasma-resonance process. Our results suggest that the ZP emission was originally generated in a completely polarized state in the O-mode and was partly converted into the X-mode near the source. Subsequently, the difference between the group velocities of the O-mode and X-mode caused the temporal delay.