Morphology of solar type II bursts caused by shock propagation through turbulent and inhomogeneous coronal plasma by A. Koval et al


Type II solar bursts are radio signatures of shock waves in the solar corona driven by solar flares or coronal mass ejections. Therefore, these bursts present complex spectral morphologies in solar dynamic spectra. In particular, the radio emission lane may separate into two thinner bands that is known as band-splitting (Vršnak et al., 2002). “Fractured” type II bursts, exhibiting spectrally indented shapes in the form of bumps or breaks, are […]

A possible new scenario for widespread solar energetic particle events by Nina Dresing et al.


A long-standing problem in solar energetic particle (SEP) studies is to pinpoint their source regions at the Sun. Potential contributions by both the flare and CME-driven shocks complicate the analysis. A certain type of SEP events shows very wide particle spreads up to all around the Sun. The mechanisms proposed so far to generate these widespread events are a very wide SEP injection region, likely a shock, or strong perpendicular […]

Two-element interferometer for millimeter-wave solar flare observations, by Yu et al.


Solar radio emission can be significantly influenced by Earth’s atmosphere when transmitting towards the Earth’s surface, due to atmospheric turbulence and the absorption of vapor and oxygen molecules etc. Consequently, antennas receive signals with a ‘dither’ component, indicating a noise signal exhibiting random variations. As a result, the sensitivity of observing systems distorts severely , especially for weaker radio bursts in the millimeter passband. Weak bursts can be usually observed […]

Solar electron beam velocities that grow Langmuir waves in the inner heliosphere by C. Y. Lorfing et al.


Solar accelerated electron beams interact with the background plasma of the solar wind to locally generate Langmuir waves and subsequently produce radio emission (Ginzburg and Zhelezniakov 1958). Numerous observations at different distances from the Sun by spacecrafts like Solar Orbiter (0.5AU) and ACE (1AU) show different energy ranges of electrons interacting with the plasma to produce Langmuir oscillations. At 0.5AU, non-thermal electrons in the deca-keV range arrive co-temporal to the […]

Data-constrained Solar Modeling with GX Simulator by G. Nita et al


In the dynamic realm of modern solar physics, where vast and diverse data sets challenge understanding, a critical need emerges for advanced data-constrained 3D modeling that combines photospheric magnetic fields measurements and a wide range of contextual electromagnetic radiation observations, which includes radio, X-ray, and extreme ultraviolet (EUV) emissions. Bridging all these available observational data constraints is imperative to create a comprehensive understanding of solar activity and phenomena. Addressing this […]

Imaging preflare broadband pulsations in the decimetric-metric wavelengths by Lv et al


Solar radio pulsations represent (quasi-)periodic or irregular short fluctuations observed from the radio flux curves or the dynamic spectra, in almost all wavelength ranges from metric to microwave (See the review by Nindos & Aurass 2007). They can be classified as broadband pulsations (BBPs) and narrowband pulsations (NBPs). Most earlier studies have focused on pulsations taking place during the impulsive or decay phases of solar flares. During the preflare stage, […]

Electron acceleration efficiency during the impulsive phase of a solar flare: X-ray and microwave observations by Kontar et al


Solar flares are known to be prolific electron accelerators, yet identifying the mechanism(s) for such efficient electron acceleration in magnetic reconnection events at the Sun (and similar astrophysical settings) presents a major challenge in Astrophysics (e.g. Holman et al 2011). Accelerated electrons with energies above $\sim 20$ keV are revealed by hard X-ray (HXR) bremsstrahlung emission, while accelerated electrons with even higher energies usually manifest themselves through radio gyrosynchrotron emission. […]

Radio measurements of coronal magnetic fields in fan-spine configurations on the Sun by B. Ryabov and A. Vrublevskis


We are striving for more accurate coronal magnetography based on changes in radio polarization as microwaves cross magnetic field lines at nearly right angles. The theory of using quasi-transverse propagation for coronal field measurements includes weak dependence on two parameters: plasma density $N_e$ and the magnetic field divergence $L_d$ (see Alissandrakis and Gary, 2021 for a review). We evaluate coronal plasma density from local differential emission measure computed from the […]

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