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

2022-05-03 91 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

2022-04-19 182 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 […]

Spectral Analysis of Solar Radio Type III Bursts from 20 kHz to 410 MHz
by K. Sasikumar Raja et al.*

2022-03-01 164 views

Solar type III radio bursts are produced by electron beams that are propagating along open magnetic field lines in the corona and interplanetary medium (IPM). Type III bursts drift from high frequency (~1 GHz) to 20 kHz at 1 AU and sometimes even beyond. It has been known for a long time that type IIIs are extremely variable, both in radio flux density and in observing frequency range. A statistical […]

Harvest of scientific results by Solar Orbiter Radio and Plasma Waves instrument
by Milan Maksimovic

2022-02-15 255 views

For a mission that has just entered its primary science phase, Solar Orbiter has already produced many remarkable results. Released on December 14, 2021, a special issue of Astronomy and Astrophysics brings together a wealth of studies and observations obtained during the mission’s cruise phase. Of the 56 articles published, 25 are based on data from the Radio & Plasma Waves (RPW) instrument (Maksimovic et al., A&A, 2020). The RPW […]

Signatures of Type III Solar Radio Bursts from Nanoflares: Modeling
by Sherry Chhabra et al.*

2022-02-01 225 views

Nanoflares are impulsive energy releases due to small breaks in coronal magnetic fields that have become stressed by photospheric convection. They are too small to be detected individually, but several lines of evidence suggest that they may be a primary candidate of coronal heating. But, whether nanoflares excite particles like full-sized flares is unknown (Vievering et al. 2021). A leading theory of particle acceleration predicts that the efficiency of acceleration […]

Characterising coronal turbulence using snapshot imaging of radio bursts in 80 – 200 MHz
by Atul Mohan

2022-01-04 161 views

Metrewave solar type-III radio bursts offer a unique means to study the properties of turbulence across coronal heights. Theoretical models have shown that the apparent intensity and size of the burst sources evolve at sub-second scales due to turbulent scattering of radio waves close to their generation sites (Arzner & Magun, 1999; Kontar et al., 2019). The advent of high cadence snapshot spectroscopic imaging capabilities in meter wavebands have made […]

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

2021-10-12 287 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. […]

The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2
by L. Harra et al*

2021-09-16 284 views

During encounter 2 of NASA’s PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019. Our aim is to investigate the source of these small and frequent bursts. We studied the behaviour of active region 12737, whose emergence and evolution coincides with the timing of the radio noise storm and determined the […]

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