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このアイテムの引用には次の識別子を使用してください: http://hdl.handle.net/10445/8327

タイトル: Fast and slow frequency-drifting millisecond bursts in Jovian decametric radio emissions
著者: Ryabov, V. B.
P., Zarka
S., Hess
A., Konovalenko
G., Litvinenko
V., Zakharenko
V.A., Shevchenko
B., Cecconi
アブストラクト: We present an analysis of several Jovian Io-related decametric radio storms recorded in 2004􀀀2012 at the Ukrainian array UTR-2 using the new generation of baseband digital receivers. Continuous baseband sampling within sessions lasting for several hours enabled us to study the evolution of multiscale spectral patterns during the whole storm at varying time and frequency resolutions and trace the temporal transformation of burst structures in unprecedented detail. In addition to the well-known frequency drifting millisecond patterns known as S bursts we detected two other classes of events that often look like S bursts at low resolution but reveal a more complicated structure in high resolution dynamic spectra. The emissions of the first type (LS bursts, superposition of L and S type emissions) have a much lower frequency drift rate than the usual quasi linearly drifting S bursts (QS) and often occur within a frequency band where L emission is simultaneously present, suggesting that both LS and at least part of L emissions may come from the same source. The bursts of the second type (modulated S bursts called MS) are formed by a wideband frequency-modulated envelope that can mimic S bursts with very steep negative (or even positive) drift rates. Observed with insu cient time-frequency resolution, MS look like S bursts with complex shapes and varying drifts; MS patterns often occur in association with (i) narrowband emission; (ii) S burst trains; or (iii) sequences of fast drift shadow events. We propose a phenomenological description for various types of S emissions, that should include at least three components: high- and low-frequency limitation of the overall frequency band of the emission, fast frequency modulation of emission structures within this band, and emergence of elementary S burst substructures, that we call “forking” structures. All together, these three components can produce most of the observed spectral structures, including S bursts with apparently very complex time-frequency structures.
研究業績種別: 原著論文/Original Paper
資料種別: Journal Article
査読有無: あり/yes
単著共著: 共著/joint
発表雑誌名,発表学会名など: Astronomy and Astrophysiscs
巻: 568
開始ページ: A53-1
終了ページ: A53-11
年月日: 2014年
出版社: EDP Sciences


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