PIC Simulation of Double Plasma Resonance and Zebra Pattern of Solar Radio Bursts
by Li et al.*

2021-05-25 124 views

Zebra patterns (ZPs) represent a spectral fine structure with equidistant or almost-equidistant stripes of enhanced intensity against a broadband emission background, frequently observed in the dynamic spectra of solar radio bursts such as type IVs. There exist many scenarios for ZPs. The most-accepted one is the model of double plasma resonance (DPR) which, as its name indicates, means simultaneous actions of two kinds of resonance instabilities, i.e., the cyclotron resonance […]

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 […]

Harmonic Electron Cyclotron Maser Emission Excited by Energetic Electrons Traveling inside a Coronal Loop
by M. Yousefzadeh et al.*

2021-04-27 132 views

Solar spikes are radio bursts closely associated with the impulsive stage of solar flares. They are characterized by extremely high brightness temperature of up to 1015 K, narrow-band, and short duration. Thousands of spikes could exist in an event. This leads researchers to suggest that solar spikes represent elementary energy release events during solar flares. Earlier studies have suggested the electron-cyclotron-maser emission (ECME) driven by energetic electrons with the loss-cone […]

Discovery of correlated evolution in noise storm source parameters: Insights on $\vec{B}$ dynamics during a microflare
by A. Mohan

2021-04-13 257 views

Solar noise storms are known to be related to small and large scale magnetic field enhancements at active regions (Elgaroy 1977, Li et al.,2017). However, the mechanism still remain unclear. Their high spectro-temporal variability and ubiquity of weak events demanded sub-second and sub-MHz scale imaging with high dynamic ranges (DRs) to reliably study emission from individual sources. Using high DR snapshot spectroscopic images from the Murchison Widefield Array, this work […]

Radio and X-ray Observations of Short-lived Episodes of Electron Acceleration in a Solar Microflare
by R. Sharma et al.

2021-03-30 156 views

In a solar flare, the plasma is locally heated and particles are accelerated to energies from a few tens of keV to MeVs. X-ray bremsstrahlung emission and radio gyrosynchrotron emission are highly complementary and provide diagnostics of the timing, location and spectral properties of flare-accelerated electrons in a broad energy range. Here we present comprehensive observations of multiple individual bursts during a GOES B1.7-class (back-ground subtracted) microflare observed jointly in […]

Analyzing the propagation of EUV waves and their connection with type II radio bursts by combining numerical simulations and multi-instrument observations
by A. Koukras et al.*

2021-03-16 132 views

EUV (EIT) waves are wavelike disturbances of enhanced extreme ultraviolet (EUV) emission that propagate away from an eruptive region. Recent years have seen much debate over their nature, with three main interpretations: the fast-mode MHD wave, the apparent wave (reconfiguration of the magnetic field), and the hybrid wave (combination of the previous two). Observations of such waves are often accompanied by type II radio bursts, which are widely considered as signature […]

On the occurrence of type IV solar radio bursts in the solar cycle 24 and their association with coronal mass ejections
by A. Kumari et al. *

2021-03-02 211 views

Coronal mass ejections are large eruptions of magnetized plasma from the Sun (Webb et. al. 2012) that are often accompanied by radio emission, generated by the energetic electrons produced during these eruptions (Gopalswamy et. al. 2004). These electrons can generate radio emission in the corona through various emission mechanisms (Melrose, 1980). The most common radio bursts associated with CMEs are type II and type IV bursts. CMEs are often accompanied […]

VLA Measurements of Faraday Rotation through a Coronal Mass Ejection Using Multiple Lines of Sight by J. E. Kooi et al.*

2021-02-16 140 views

The Sun is the main source of space weather, and one type of solar event that is critical to space weather is a coronal mass ejection. Coronal mass ejections (CMEs) are large eruptions of magnetized plasma from the Sun that produce energetic particles, which can cause geomagnetic storms on Earth. One method that has proven successful in determining the strength and structure of the coronal magnetic field is Faraday rotation […]

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