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

2021-08-31 290 views

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 […]

Parametric simulation studies on the wave propagation of solar radio emission: the source size, duration, and position by Zhang et al.*

2021-05-11 219 views

The imaging and spectroscopy observations of solar radio bursts can provide information on the non-thermal electrons associated with the transient energy release in the solar active region and the parameters of the background plasma. However,  the corona plasma is an inhomogeneous refractive media for solar radio waves. Propagation effects, namely the refraction and scattering of waves, can cause the deformation of the observed radio source, including the expansion of the […]

Radio echo in the turbulent corona and simulations of solar drift-pair radio bursts observed with LOFAR
by Kuznetsov et al

2020-08-18 277 views

Drift-pair bursts are a rare and mysterious type of fine spectral structures in the low-frequency domain of solar radio emission. First identified by Roberts (1958), they appear in the dynamic spectrum as two parallel frequency-drifting bright stripes separated in time; the trailing stripe seems to repeat the morphology of the leading one with a typical delay of ~1–2 s (see, e.g., Figure 1). Recent imaging spectroscopy observations with the LOw-Frequency […]

Density and magnetic field turbulence in solar flares estimated from radio zebra observations
by M. Karlicky and L. Yasnov

2020-07-14 165 views

Solar flares are characterized by fast plasma flows. In such plasma flows owing to the Kelvin-Helmholtz instability the maqnetohydrodynamic turbulence can be generated. Although, the turbulence plays an important role in solar flares, e.g., in acceleration of particles, a knowledge about the level of  this turbulence is still very limited.  In the present study we estimate the levels of this turbulence. For this purpose we use observations of the so called zebra […]

Observing onset of turbulent fast magnetic reconnection in solar microflares
by L. P. Chitta and A. Lazarian

2020-04-14 189 views

Magnetic reconnection is a key process in astrophysical and space plasmas that converts magnetic energy into other forms of energy. It drives gamma-ray bursts, solar flares, and accelerates particles. A fast reconnection is necessary to explain the explosive nature of flares and bursts. However, conditions for the onset of fast reconnection are a topic of intense debate. Simulations of magnetic reconnection in 2D have shown that the current sheet is […]

Density Fluctuations in the Solar Wind Based on Type III Radio Bursts Observed by Parker Solar Probe
by V. Krupar et al.*

2020-03-31 270 views

Type III bursts belong among the strongest radio signals routinely observed by both space-borne and ground-based instrumentations. They are generated via the plasma emission mechanism, when beams of suprathermal electrons interact with the ambient plasma triggering radio emissions at the plasma frequency (the fundamental emission) or at its second harmonic (the harmonic emission). As the electron beams propagate outward from the Sun, radio emissions are generated at progressively lower frequencies […]

Fast reconnection in turbulent media
by A. Lazarian

2020-03-17 230 views

Solar flares, similar to many other astrophysical energetic processes, are related to magnetic reconnection. During these events magnetic energy is transferred from other forms of energy, mostly heat and energetic particles. Traditionally, the goal of various models of magnetic reconnection was to explain the rate of this energy transfer. However, the flares are just one of the processes that involves magnetic reconnection. If one imagines any complex motion in a […]

On the Source Position and Duration of a Solar Type III Radio Burst Observed by LOFAR
by P. Zhang et al.*

2020-01-21 508 views

Type III radio bursts are generated by non-thermal electron beams propagating through the solar corona and interplanetary space. In dynamic spectra, the flux of solar type III radio bursts have a time profile of rising and decay phases at a given frequency, which has been actively studied since the 1970s. There are several factors that may contribute to the observed duration of a type III radio burst: 1) The velocity […]

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