First Frequency-time-resolved Imaging Spectroscopy Observations of Solar Radio Spikes
by D. L. Clarkson et al.*

2021-10-12 270 views

Solar radio spikes are short duration, narrowband radio bursts that are signature of the acceleration of non-thermal electrons in solar flares. They are observed over a wide range of frequencies from the tens of MHz (Melnik et al. 2014) to the GHz range (Benz et al. 1992), and have some of the shortest durations and narrow bandwidths of any solar radio bursts. The origin of spikes is not fully understood. […]

Properties of High-Frequency Type II Radio Bursts and Their Relation to the Associated Coronal Mass Ejections
by A.C. Umuhire et al.*

2021-09-28 204 views

Type II radio bursts are slow-drifting and long-lasting radio emission produced by nonthermal electrons accelerated at shocks propagating through the solar corona and interplanetary medium (Nelson & Melrose, 1985). The accelerated electrons generate Langmuir waves, which get converted into electromagnetic radiation by the plasma emission mechanism first identified by Ginzburg & Zhelezniakov (1958). Currently, there is a common understanding that type II radio bursts are produced by shocks formed ahead […]

New results on the direct observations of thermal radio emission from a solar coronal mass ejection
by R. Ramesh et al.*

2021-08-03 165 views

Coronal mass ejections (CMEs) are large scale and energetic eruptions in the solar atmosphere during which $\approx$10$^{12}$-10$^{16}$g of magnetized coronal plasma are ejected into the heliosphere at speeds ranging from $\approx$100-3000km/s. They are mostly observed in whitelight using coronagraphs which use an occulter to block the bright light from the solar photosphere so that structures like CMEs can be observed with better contrast. But the size of the coronagraph occulters […]

On the occurrence of type IV solar radio bursts in the solar cycle 24 and their association with coronal mass ejections
by A. Kumari et al. *

2021-03-02 225 views

Coronal mass ejections are large eruptions of magnetized plasma from the Sun (Webb et. al. 2012) that are often accompanied by radio emission, generated by the energetic electrons produced during these eruptions (Gopalswamy et. al. 2004). These electrons can generate radio emission in the corona through various emission mechanisms (Melrose, 1980). The most common radio bursts associated with CMEs are type II and type IV bursts. CMEs are often accompanied […]

VLA Measurements of Faraday Rotation through a Coronal Mass Ejection Using Multiple Lines of Sight by J. E. Kooi et al.*

2021-02-16 143 views

The Sun is the main source of space weather, and one type of solar event that is critical to space weather is a coronal mass ejection. Coronal mass ejections (CMEs) are large eruptions of magnetized plasma from the Sun that produce energetic particles, which can cause geomagnetic storms on Earth. One method that has proven successful in determining the strength and structure of the coronal magnetic field is Faraday rotation […]

Estimate of Plasma Temperatures across a CME-driven Shock from a Comparison between EUV and Radio Data
by F. Frassati et al.*

2020-12-01 172 views

Type II radio bursts, produced near the local plasma frequency and/or its harmonic by energetic electrons accelerated by shock waves moving outward through the inner heliosphere, have long been recognized as evidence of shock waves origin and propagation in the solar corona. In this work, we analyze the early evolution of a coronal shock wave, associated with a prominence eruption, with the aim of investigating the properties of the compressed […]

Polarisation and source structure of solar stationary type IV radio bursts
by C. Salas-Matamoros and L. Klein

2020-09-08 195 views

A coronal mass ejection (CME) is a phenomenon which produces large-scale ejections of mass and magnetic field from the lower corona into the interplanetary space (e.g. Forbes, 2000). The ejection of CMEs is often accompanied by the radio emission from non-thermal electrons. Particularly, stationary type IV continua are thought to be emitted by electrons in closed magnetic structures in the wake of the rising CME. Although basic properties, such as […]

Fast CME caused by the eruption of a quiescent prominence
by V. Grechnev and I. Kuzmenko

2020-06-09 175 views

CMEs can be the sources of space-weather disturbances. Shock waves expanding ahead of fast CMEs and associated flares are the probable sources of energetic protons. Two categories of CMEs have traditionally been identified depending on the presence of conspicuous chromospheric emissions during their development. Flare-associated CMEs erupt from active regions, carry stronger magnetic fields, can reach higher speeds and cause stronger space-weather disturbances. Non-flare-associated CMEs develop in eruptions of large […]

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