Community of European Solar Radio Astronomers – Page 19

Shock location and CME 3-D reconstruction of a solar type II radio burst with LOFAR
by P. Zucca et al.*

2018-10-30

Type II radio bursts are the result of shocks in the solar atmosphere and they can be observed ranging from sub-metric to kilometric wavelengths (~400 MHz to ~0.4 MHz). Coronal mass ejections initiate most of the metric type II (m-type II) bursts. The region of a CME responsible for driving the shock might be different for each event and has not yet been comprehensively identified. Multiple scenarios have been suggested, […]

Non-radial propagation of energetic electrons in solar corona by A. Klassen et al.

2018-10-16

STEREO and near-Earth multi-spacecraft observations of solar energetic particle (SEP) events have revealed that some events show quite unexpected intensity distributions at 1 AU (Dresing et al. 2012, Lario et al. 2013). They can be much broader (circumsolar) (Gómez-Herrero et al. 2015), non-symmetric, and sometimes irregular showing so-called finger distribution (Klassen et al. 2016). It had been suggested that these non-symmetric and irregular distributions, among others, may result from non-radial […]

Alternative zebra-structure models in solar radio emission
by Chernov G.P.

2018-10-02

There is ongoing discussion in the literature about the nature of zebra-structure (ZS) in type IV radio bursts (Chernov, 2011). We showed the possibility of a model with whistler waves to explain many thin components of ZS stripes, taking into account the effects of scattering of the whistlers on fast particles. Here, we show some complex examples of observations of ZS bursts in different wave ranges, which are difficult to […]

Size distributions of solar proton events and their asso-ciated soft X-ray flares based on the maximum likelihood estimator
by E.W. Cliver and E. D’Huys

2018-09-18

It has been known for some time that the size distributions of solar radio bursts and soft X-ray (SXR) flares have steeper power-law slopes (~1.8) than those (~1.2) of solar energetic proton (SEP) events. Hudson (1978) suggested three possibilities for this difference: (1) proton flares are fundamentally different from ordinary flares; (2) proton flares represent the large end of the total energy distribution of ordinary flares; and (3) proton flare […]

Decimetric emission 500 arcseconds away from a flaring site: Possible scenarios from GMRT solar radio observations
by Bisoi et al.*

2018-09-04

The displaced positions of radio sources away from the true source locations are usually observed in radio images at metric and decimetric wavelengths (Duncan 1979, Benz et al. 2002, Kundu et al., 2006, Kontar et al., 2017, Mann et al., 2018). The displaced radio source location is the apparent source position, that result from the scattering of radio waves (Kontar et al. 2017) or by coronal propagation effects (Mann et […]

Modulation of radio emission, fast magnetoacoustic waves and magnetic field measurements in the solar corona with LOFAR
by Kolotkov et al*

2018-08-21

Fast magnetoacoustic wave trains are a promising seismological probe of the corona, revealing the magnetic connectivity and providing the estimation of the absolute value of the coronal magnetic field. Low-frequency radio observations allow for the detection of fast wave trains in middle and upper corona, above the field-of-view of EUV imagers and spectrographs, via the modulation of the radio emission by the variations of the electron concentration. We present the […]

An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure
by Ruisheng Zheng et al.*

2018-08-07

Extreme-ultraviolet (EUV) waves are spectacular horizontally propagating disturbances in the low solar corona. If an EUV wave encounters an ambient coronal structure it may trigger another horizontal wave, which is always named a ‘secondary wave’ (SW). We present the first example of upward SWs in a streamer-like structure, a bright loop-like structure developing over an active region, after the passing of an EUV wave. The EUV wave was associated with […]

Long-lasting injection of solar energetic electrons into the heliosphere
by N. Dresing et al.

2018-07-24

The solar energetic particle (SEP) event from 26 Dec 2013 was a so-called widespread event observed by multiple spacecraft. The two STEREO and one close to Earth spacecraft spanned a total longitudinal angle of 210 degrees at that time. Together with the 25 Feb 2014 (Lario et al., 2016, Klassen et al., 2016) this is the widest event ever observed with the STEREO spacecraft. Unusually long-lasting SEP anisotropies together with […]

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