turbulence

Temporally resolved Type III solar radio bursts in the frequency range 3-13 MHz by A. Vecchio et al.

2024-12-17

Type III radio bursts are the most common coherent radio emission produced by the Sun. They are characterized by a rapid drift in time towards lower frequencies and represent an indirect signature of energetic electrons produced at the Sun during a flare and propagating through the plasma of the corona and the interplanetary medium. Type III bursts are observed over a wide range of frequencies ranging from about ∼500 MHz […]

The angular and frequency dependence of solar radio burst rise and decay times using multi-spacecraft observations by Nicolina Chrysaphi et al.

2024-08-27

Density fluctuations populating the heliosphere interfere with propagating radio photons, altering their trajectories through frequency-dependent effects like scattering. Crucially, these density fluctuations are anisotropic, leading to anisotropic scattering and directional radio-wave propagation. This means that observers at different positions may obtain different estimations of radio properties. Such effects are particularly evident in solar radio bursts which are emitted through the plasma emission mechanism. It has been shown that detectors at […]

Energetics of compressive waves in the solar corona by Francesco Azzollini et al

2024-07-02

Inelastic scattering off moving or oscillating density fluctuations leads to broadening of radio signals propagating in the solar corona and solar wind. Using an anisotropic density fluctuation model from the kinetic scattering theory for solar radio bursts, we deduce the plasma velocities (perpendicular to the line of sight) required to explain observations of spacecraft signal frequency broadening. The kinetic energy associated with these inferred bulk velocities cascades to smaller and […]

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An Interactive Visual Tool for the Anisotropic Scattering of Solar Radio Bursts by Daniel L. Clarkson et al

2024-02-06

The turbulent heliosphere has a significant effect on the observed characteristics of radio emission produced in, or viewed through, the solar atmosphere. In particular, radio-wave scattering on density irregularities can broaden the observed decay times and source sizes, and shift the apparent source position. Both radio burst observations and simulations have demonstrated that the turbulence is anisotropic, which can explain both the observed decay times and source sizes simultaneously. Considering […]

Source positions of an interplanetary type III radio burst and anisotropic radio-wave scattering by X. Chen et al.

2023-12-19

Interplanetary solar radio type III bursts provide the means to remotely study and track energetic electrons propagating in the interplanetary medium. Due to the lack of direct radio source imaging, several methods have been developed to determine the source positions from space-based observations. Moreover, none of the methods consider the propagation effects of anisotropic radio-wave scattering, which would strongly distort the trajectory of radio waves, delay their arrival times, and […]

Anisotropic density turbulence variation from the low corona to 1 au as deduced from solar radio observations by E. Kontar et al.

2023-11-30

Density turbulence in the solar corona and solar wind is evident via the properties of solar radio bursts; angular scattering-broadening of extra-solar radio sources observed through the solar atmosphere, and can be measured in-situ in the solar wind. A viable density turbulence model should simultaneously explain all three types of density fluctuation observations. Solar radio bursts (e.g. Type I, II, III) observed below ~1 GHz are produced predominantly via plasma […]

Solar coronal density turbulence and magnetic field strength at the source regions of two successive metric type II radio bursts by Ramesh et. al.

2023-03-14

Solar type II radio bursts appear in the spectrograph records as slowly drifting emission lanes from high to low frequencies. They are due to plasma oscillations caused by the electrons accelerated at the MHD shocks propagating outward in the solar atmosphere (Nelson et al. 1985, Mann et al. 1995). The plasma emission in a magnetic field gets split as ordinary ($O$) and extraordinary ($X$) modes. Since the propagation characteristics of […]

Langmuir wave motion observed in the most intense radio sources in the sky
by H. Reid and E. Kontar

2021-08-31

The Sun routinely produces energetic electrons in its outer atmosphere that subsequently travel through interplanetary space. These electron beams generate Langmuir waves in the background plasma, producing type III radio bursts that are the brightest radio sources in the sky (Suzuki & Dulk, 1985). These solar radio bursts also provide a unique opportunity to understand particle acceleration and transport which is important for our prediction of extreme space weather events […]

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