Third and fourth harmonics of electromagnetic emissions by a weak beam in a solar wind plasma with random density fluctuations by C. Krafft

2022-11-22 63 views

Electromagnetic emissions at the third harmonic of the plasma frequency $\omega _{p}$ have been reported during the occurrence of type II and type III solar radio bursts (e.g. Zlotnik 1978, Zlotnik et al. 1998, Cairns; 1986), even if rarely and sometimes controversially. Recently the Wind spacecraft detected several events exhibiting third harmonic emissions in interplanetary type III bursts observed locally near 1 AU (Reiner and MacDowald; 2019). For the first […]

Characteristics of stripes-pattern radio-emission sources by Khaled Alielden

2022-10-18 97 views

Investigating the generation mechanism for the stripes-pattern radio spectra is important to understand the dynamics of non-thermal electrons in several astronomical objects, including the Sun, Jupiter, and the Crab Pulsar. A new analytical study is carried out to identify the plasma characteristics of fiber- and zebra-pattern emission sources without an underlying density or magnetic model. The study suggests that the plasma condition of the source region for zebra pattern emission […]

Narrowband Spikes Observed During the 13 June 2012 Flare in the 800 – 2000 MHz Range by Marian Karlicky et al

2022-09-06 107 views

The solar radio spikes can provide detailed information about plasma processes in solar flares on kinetic scales. Among them, the decimetric spikes belong to the most interesting ones because they are recorded in some cases close to the starting frequency of Type-III bursts and in relation to hard X-ray emissions. Stepanov et al. (1999) and Bárta and Karlický (2001) presented models where spike frequencies correspond to those of the upper-hybrid […]

Tackling the Unique Challenges of Low-frequency Solar Polarimetry with the Square Kilometre Array Low Precursor: The Algorithm by Devojyoti Kansabanik et al

2022-08-23 88 views

The solar corona comprises hot magnetized plasma. Coronal magnetic fields are well known to be one of the crucial parameters determining the physics of the solar corona and are vital drivers of Space Weather. Despite the fact that the importance of coronal magnetic fields has been recognised for a long, in practice, they remain rather hard to measure. The polarization properties of coronal emission at low radio frequencies can, in […]

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

2022-07-19 325 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.*

2022-07-05 110 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

2022-06-21 145 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.*

2022-06-07 111 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 […]

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