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Context. Observations of solar type II radio bursts provide a unique opportunity to analyze the non-thermal electrons accelerated by coronal shocks and also to diagnose the plasma density distribution in the corona. However, there are very…

太阳与恒星天体物理 · 物理学 2024-03-29 Peijin Zhang , Diana E. Morosan , Pietro Zucca , Sanna Normo , Bartosz Dabrowski , Andrzej Krankowski , Christian Vocks

The first appearance of radio type II burst emission at decameter-hectometer (DH) waves typically occurs in connection, and often simultaneously, with other types of radio emissions. As type II bursts are signatures of propagating shock…

太阳与恒星天体物理 · 物理学 2021-05-18 Silja Pohjolainen , Nasrin Talebpour Sheshvan

Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II…

太阳与恒星天体物理 · 物理学 2015-05-20 W. Su , X. Cheng , M. D. Ding , P. F. Chen , J. Q. Sun

Aims: Emission of radio waves from plasmas through plasma emission with fundamental and harmonic frequencies is a familiar process known from solar type II radio bursts. Current models assume the existence of counterstreaming electron beam…

太阳与恒星天体物理 · 物理学 2014-05-08 Urs Ganse , Patrick Kilian , Felix Spanier , Rami Vainio

Context. The origin of coronal type-II radio bursts and of their band-splitting are still not fully understood. Aims. To make progress in solving this problem on the basis of one extremely well observed solar eruptive event. Methods. The…

太阳与恒星天体物理 · 物理学 2015-06-11 I. Zimovets , N. Vilmer , A. C. -L. Chian , I. Sharykin , A. Struminsky

Type II radio bursts are thought to be produced by shock waves in the solar atmosphere. However, what magnetic conditions are needed for the generation of type II radio bursts is still a puzzling issue. Here, we quantify the magnetic…

太阳与恒星天体物理 · 物理学 2022-05-11 W. Su , T. M. Li , X. Cheng , L. Feng , P. J. Zhang , P. F. Chen , M. D. Ding , L. J. Chen , Y. Guo , Y. Wang , D. Li , L. Y. Zhang

Aims. We examine high time resolution dynamic spectra for fine structures in type II solar radio bursts Methods. We used data obtained with the (SAO) receiver of the Artemis-JLS (ARTEMIS-IV) solar radio spectrograph in the 450-270 MHz range…

太阳与恒星天体物理 · 物理学 2019-04-17 S. Armatas , C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , E. Mitsakou , P. Tsitsipis , A. Kontogeorgos

The Sun produces the most powerful explosions in the solar system, solar flares, that can also be accompanied by large eruptions of magnetised plasma, coronal mass ejections (CMEs). These processes can accelerate electron beams up to…

太阳与恒星天体物理 · 物理学 2023-07-05 D. E. Morosan , J. Pomoell , A. Kumari , E. K. J. Kilpua , R. Vainio

Narrowband bursts (spikes) appear on dynamic spectra from microwave to decametric frequencies. They are believed to be manifestations of small-scale energy release through magnetic reconnection. We study the position of the spike-like…

太阳与恒星天体物理 · 物理学 2022-03-30 S. Armatas , C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , A. Kontogeorgos , P. Tsitsipis , X. Moussas

Context. Type II radio bursts are solar radio burst associated with coronal shocks. Type II bursts usually exhibit fine structures in dynamic spectra that represent signatures of accelerated electron beams. So far, the sources of individual…

太阳与恒星天体物理 · 物理学 2023-10-13 Peijin Zhang , Diana Morosan , Anshu Kumari , Emilia Kilpua

Type I noise storms constitute a sizeable faction of the active-Sun radio emission component. Observations of isolated instances of such bursts, in the swept-frequency-mode at metric wavelengths, have remained sparse, with several unfilled…

天体物理学 · 物理学 2009-11-10 G. A. Shanmugha Sundaram , K. R. Subramanian

Solar flare is one of the most important solar activities which emit all electromagnetic waves in gigantic burst. The radio emission can be used to determine the physical properties of the solar flares. The e-CALLISTO worldwide network is…

太阳与恒星天体物理 · 物理学 2023-08-04 D P S Nilagarathne , J Adassuriya , H O Wijewardane

Type-I solar noise storms are perhaps the most commonly observed active radio emissions from the Sun at meter-wavelengths. Noise storms have a long-lived and wideband continuum background with superposed islands of much brighter narrowband…

太阳与恒星天体物理 · 物理学 2024-11-22 Surajit Mondal , Devojyoti Kansabanik , Divya Oberoi , Soham Dey

Type II solar radio bursts are commonly associated with shocks generated by coronal mass ejections (CMEs), where plasma waves are excited by magnetohydrodynamic (MHD) processes and converted into radio waves at the local plasma frequency or…

太阳与恒星天体物理 · 物理学 2025-10-07 Anshu Kumari , Nat Gopalswamy

It has been suggested that type II radio bursts are due to energetic electrons accelerated at coronal shocks. Radio observations, however, have poor or no spatial resolutions to pinpoint the exact acceleration locations of these electrons.…

太阳与恒星天体物理 · 物理学 2015-06-04 S. W. Feng , Y. Chen , X. L. Kong , G. Li , H. Q. Song , X. S. Feng , Ying Liu

Solar flare termination shocks have been suggested as one of the promising drivers for particle acceleration in solar flares, yet observational evidence remains rare. By utilizing radio dynamic spectroscopic imaging of decimetric stochastic…

太阳与恒星天体物理 · 物理学 2019-10-16 Bin Chen , Chengcai Shen , Katharine K. Reeves , Fan Guo , Sijie Yu

Solar radio type II bursts serve as early indicators of incoming geo-effective space weather events such as coronal mass ejections (CMEs). In order to investigate the origin of high-frequency type II bursts (HF type II bursts), we have…

Violent solar eruptions are often accompanied by relativistic beams of charged particles. In the solar context, they are referred to as SPEs (Solar Particle Events) and are known to generate a characteristic swept-frequency radio burst. Due…

太阳与恒星天体物理 · 物理学 2020-07-15 H. K. Vedantham

Shocks in the solar corona can accelerate electrons that in turn generate radio emission known as type II radio bursts. The characteristics and morphology of these radio bursts in the dynamic spectrum reflect the evolution of the shock…

太阳与恒星天体物理 · 物理学 2025-11-19 P. Zucca , P. Zhang , K. Kozarev , M. Nedal , M. Mancini , A. Kumari , D. E. Morosan , B. Dabrowski , P. T. Gallagher , A. Krankowski , C. Vocks