First detection of metric emission from a solar surge by Costas Alissandrakis et al.*

2022-07-19 305 views

Practically all solar phenomena observed in radio wavelengths have their counterpart in other regions of the electromagnetic spectrum. Metric solar bursts are an exception to the above statement. Although we have a basic understanding of their origin, some of their counterparts in other spectral ranges have not been identified, with the exception of the so called “radio CMEs”. This is apparently because metric bursts result from coherent plasma emission, which […]

Solar radio bursts associated with in situ detected energetic electrons in solar cycles 23 and 24
by R. Miteva et al.*

2022-07-05 95 views

We present a short overview on the results from the first association analysis between in situ observed solar energetic electrons at 1 AU using the ACE/EPAM instrument (Samwel and Miteva, 2021) and radio bursts of type II, III and IV. The statistical analysis is performed over the last two solar cycles (SCs), 23 and 24 (1997-2019). All previous research has focused on energetic protons, whereas we aimed to compare in […]

Trieste CALLISTO Station Setup and Observations of  Solar Radio Bursts
by A. Marassi and C. Monstein

2022-06-21 129 views

A solar radio burst (SRB) is the intense solar radio emission often related to a solar flare and one of the possibly extreme space weather events which may affect Earth’s ionosphere and signal propagation, wireless communication, power grids and navigation systems. If an SRB occurs with the enhancement in L band radio flux, it could influence the Global Navigation Satellite Systems (GNSS) signals through direct radio wave interferences. The major […]

Subarcsecond imaging of a solar active region filament with ALMA and IRIS
by da Silva Santos et al.*

2022-06-07 104 views

Filaments (or prominences) are “clouds” of cool (<104 K) material suspended in the solar corona by up to tens of megameters above the photosphere, and they can be broadly divided into quiescent filaments and active region (AR) filaments. Although both of these structures have been observed for a long time, particularly in recent years by NASA’s IRIS telescope, there are open questions on the magnetic topology of filaments and the […]

Density Turbulence and the Angular Broadening of Outer Heliospheric Radio Sources at High Latitudes and in the Ecliptic Plane
by S. Tasnim et al.*

2022-05-24 108 views

We investigate angular broadening of radio wave scattering by density irregularities in the outer heliosphere and the very local interstellar medium (VLISM), incorporating an inner scale, latitudinal, and radial dependencies for the density fluctuation spectra and radiation propagation paths both near and out of the ecliptic plane. Outer Heliospheric Radio Emission Low-frequency radio wave emission was discovered in the distant heliosphere by the Voyager missions. A number of investigations [e.g., […]

Langmuir-Slow Extraordinary Mode Magnetic Signature Observations with Parker Solar Probe
by A. Larosa et al

2022-05-03 116 views

Langmuir-Slow extraordinary mode (L-SE) waves have been routinely observed in the Solar wind and in Earth’s electron foreshock since the early age of the space exploration. They are intimately connected to the plasma emission mechanism for the type III and type II radio emissions. In fact, the generally accepted scenario is that L-SE waves are mode-converted to freely propagating electromagnetic emission at the plasma frequency. However,  the details of the […]

LOFAR size and shape measurements of solar metric radio burst sources
by Gordovskyy et al

2022-04-19 219 views

The plasma density and magnetic field in the upper solar corona and inner heliosphere are not sufficient to produce detectable bremsstrahlung hard X-ray or gyrosynchrotron microwave emissions, making metric and decametric coherent radio emissions the only tool for probing energetic electrons in these layers of the solar atmosphere (e.g. McLean & Labrum 1985; Pick & Vilmer 2008 as reviews). This source of information is vital to understanding the underlying mechanisms […]

Fundamental electromagnetic emissions by a weak electron beam in solar wind plasmas with density fluctuations
by C. Krafft and P. Savoini

2022-04-05 141 views

Solar radio bursts of Type III were currently observed since decades in the interplanetary space (Reid and Ratcliffe, 2014). They result from a series of successive processes arising in solar coronal and wind plasmas where Langmuir wave turbulence is radiated by electron beams generated during flares, leading ultimately to the emission of electromagnetic waves at the fundamental plasma frequency $\omega _{p}$ and its second harmonic. The Letter by Krafft and […]

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