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Understanding the origins of stellar radio emission can provide invaluable insight into the strength and geometry of stellar magnetic fields and the resultant space weather environment experienced by exoplanets. Here, we present the first…

太阳与恒星天体物理 · 物理学 2018-02-21 Joe Llama , Moira M. Jardine , Kenneth Wood , Gregg Hallinan , Julien Morin

Coronal mass ejections (CMEs) on stars other than the Sun have proven very difficult to detect. One promising pathway lies in the detection of type II radio bursts. Their appearance and distinctive properties are associated with the…

Aims. Coronal Mass Ejections (CMEs) are the most fascinating explosion in the solar system; however, their formation is still not fully understood. Methods. Here, we investigate a well-observed CME on 2021 May 07 that showed a typical…

太阳与恒星天体物理 · 物理学 2022-10-26 B. T. Wang , X. Cheng , H. Q. Song , M. D. Ding

Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma that may cause severe geomagnetic storms if Earth-directed. Here we report a rare instance with comprehensive in situ and remote sensing observa- tions of a CME…

The observed properties (i.e., source size, source position, time duration, decay time) of solar radio emission produced through plasma processes near the local plasma frequency, and hence the interpretation of solar radio bursts, are…

As the most energetic eruptions in the solar system, coronal mass ejections (CMEs) can produce shock waves at both their front and flanks as they erupt from the Sun into the heliosphere. However, the amount of energy produced in these…

太阳与恒星天体物理 · 物理学 2015-06-23 David M. Long , Deborah Baker , David R. Williams , Eoin P. Carley , Peter T. Gallagher , Pietro Zucca

Coronal Mass Ejections (CMEs) are believed to be effective in producing shocks in the solar corona and the interplanetary space. One of the important signatures of shocks and shock acceleration are Type II solar radio bursts that drift with…

太阳与恒星天体物理 · 物理学 2018-11-28 Nicolina Chrysaphi , Eduard P. Kontar , Gordon D. Holman , Manuela Temmer

The most intense solar energetic particle events are produced by coronal mass ejections (CMEs) accompanied by intense type II radio bursts below 15 MHz. Understanding where these type II bursts are generated relative to an erupting CME…

太阳与恒星天体物理 · 物理学 2021-12-08 Alexander M. Hegedus , Ward B. Manchester , Justin C. Kasper

We use the cyclotron-maser theory to explain the core emission from the magnetosphere of pulsars. As a kind of direct and efficient maser type of emission, it can give rise to escaping radiation with extremely high brightness temperature…

天体物理学 · 物理学 2009-10-30 Chun-yu Ma , Ding-yi Mao , De-yu Wang , Xin-ji Wu

Aims: We identify the source of fast-drifting decimetric-metric radio emission that is sometimes observed prior to the so-called flare continuum emission. Fast-drift structures and continuum bursts are also observed in association with…

天体物理学 · 物理学 2008-08-26 S. Pohjolainen

The spectra of coronal mass ejections (CMEs) in the low corona play a crucial role in understanding their origins and physical mechanism, and enhancing space weather forecasting. However, capturing these spectra faces significant…

太阳与恒星天体物理 · 物理学 2025-04-01 Lami Chan , Xianyong Bai , Hui Tian , Yufei Feng , Yu Xu , Tibor Török , Yuhang Gao , Tanmoy Samanta , Zheng Sun

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

Aims: Solar radio type II bursts are rarely seen at frequencies higher than a few hundred MHz. Since metric type II bursts are thought to be signatures of propagating shock waves, it is of interest to know how these shocks, and the type II…

天体物理学 · 物理学 2009-11-13 S. Pohjolainen , J. Pomoell , R. Vainio

Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the coronae of stars. Understanding the plasma processes involved in CME initiation has applications to space weather forecasting and laboratory plasma experiments.…

太阳与恒星天体物理 · 物理学 2018-03-21 Alexander W. James , Gherardo Valori , Lucie M. Green , Yang Liu , Mark C. M. Cheung , Yang Guo , Lidia van Driel-Gesztelyi

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

Measuring the physical parameters of Coronal Mass Ejections (CMEs), particularly their entrained magnetic field, is crucial for understanding their physics and for assessing their geo-effectiveness. At the moment, only remote sensing…

太阳与恒星天体物理 · 物理学 2020-08-13 Surajit Mondal , Divya Oberoi , Angelos Vourlidas

Observed oscillations of coronal loops in EUV lines have been successfully used to estimate plasma parameters in the inner corona (< 0.2 R_0, where R_0 is the solar radius). However, coronal seismology in EUV lines fails for higher…

Solar flares and coronal mass ejections (CMEs) can accelerate electrons, causing bursts such as type IV emissions in the solar radio continuum. Although radio spectroscopy is a powerful diagnostic tool for the corona, the origin and…

太阳与恒星天体物理 · 物理学 2025-09-03 Edin Husidic , Nicolas Wijsen , Immanuel Christopher Jebaraj , Angelos Vourlidas , Luis Linan , Rami Vainio , Stefaan Poedts

We simulate possible stellar coronal mass ejection (CME) scenarios over the magnetic cycle of $\epsilon$ Eridani (18 Eridani; HD 22049). We use three separate epochs from 2008, 2011, and 2013, and estimate the radio emission frequencies…

Two coherent radio emission mechanisms operate in stellar coronae: plasma emission and cyclotron emission. They directly probe the electron density and magnetic field strength respectively. Most stellar radio detections have been made at…

太阳与恒星天体物理 · 物理学 2020-11-11 H. K. Vedantham