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Caroubalos, C.; Maroulis, Dimitris; Patavalis, N.; Bougeret, Jean‐Louis; Dumas, G.; Perche, C.; Alissandrakis, C. E.; Hillaris, A.; Moussas, X.; Preka‐Papadema, P.; Kontogeorgos, A.; Tsitsipis, P.; Kanelakis, G.

doi:10.1023/a:1011178517069

Cited by 48 publications

(31 citation statements)

References 4 publications

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“…• The Artemis-IV radio-spectrograph 2 (Caroubalos et al, 2001;Kontogeorgos et al, 2006aKontogeorgos et al, ,b, 2008, observes in the frequency range 20-650 MHz. ).…”

Section: Observations and Data Selectionmentioning

confidence: 99%

Interplanetary Type IV Bursts

2016

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We study the characteristics of moving type IV radio bursts which extend to the hectometric wavelengths (interplanetary type IV or type IV IP bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz-20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraiso and Izmiran Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs and SXR flares. The majority of the events (45) were characterized as compact; their duration was on average 106 minutes. This type of events was, mostly, associated with M-and X-class flares (40 out of 45) and fast CMEs; 32 of these events had CMEs faster than 1000 km s −1 . Furthermore, in 43 compact events the CME was, possibly, subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long lived type IV IP bursts was detected, with duration from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal type IV bursts. The latter were found to persist on the disk, for tens of hours to days. Prominent among them was the unusual interplanetary type IV burst of 18-23 May 2002, which is the longest event in the Wind /WAVES catalog. The three extended events were, usually, accompanied by a number of flares, of GOES class C in their majority, and of CMEs, many of which were slow and narrow.

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“…• The Artemis-IV radio-spectrograph 2 (Caroubalos et al, 2001;Kontogeorgos et al, 2006aKontogeorgos et al, ,b, 2008, observes in the frequency range 20-650 MHz. ).…”

Section: Observations and Data Selectionmentioning

confidence: 99%

Interplanetary Type IV Bursts

2016

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“…The ARTEMIS solar radio spectrograph is located at Thermopylae, Greece (Caroubalos et al 2001). At the times of the events analyzed in this article, the instrument covered the frequency range from 110 to 687 MHz, using two receivers operating in parallel.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

On the relationship of shock waves to flares and coronal mass ejections

Nindos

Alissandrakis

Hillaris

et al. 2011

A&A

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Context. Metric type II bursts are the most direct diagnostic of shock waves in the solar corona. Aims. There are two main competing views about the origin of coronal shocks: that they originate in either blast waves ignited by the pressure pulse of a flare or piston-driven shocks due to coronal mass ejections (CMEs). We studied three well-observed type II bursts in an attempt to place tighter constraints on their origins. Methods. The type II bursts were observed by the ARTEMIS radio spectrograph and imaged by the Nançay Radioheliograph (NRH) at least at two frequencies. To take advantage of projection effects, we selected events that occurred away from disk center. Results. In all events, both flares and CMEs were observed. In the first event, the speed of the shock was about 4200 km s −1 , while the speed of the CME was about 850 km s −1 . This discrepancy ruled out the CME as the primary shock driver. The CME may have played a role in the ignition of another shock that occurred just after the high speed one. A CME driver was excluded from the second event as well because the CMEs that appeared in the coronagraph data were not synchronized with the type II burst. In the third event, the kinematics of the CME which was determined by combining EUV and white light data was broadly consistent with the kinematics of the type II burst, and, therefore, the shock was probably CME-driven. Conclusions. Our study demonstrates the diversity of conditions that may lead to the generation of coronal shocks.

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“…In order to make sure that this is the case, we examined dynamic spectrograms observed by the radio spectrographs of the Potsdam Astrophysical Institute at Tremsdorf (Mann et al 1992, henceforth OSRA), the University of Athens (ARTEMIS, Caroubalos et al 2001), and IZMIRAN near Moscow 1 . The metre wave spectra displayed numerous densely packed bursts.…”

Section: Radio Identification Of Magnetic Flux Tubes In the Coronamentioning

confidence: 99%

Open magnetic flux tubes in the corona and the transport of solar energetic particles

Klein¹,

Krucker²,

Lointier³

et al. 2008

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We investigate how magnetic fields guide energetic particles through the corona into interplanetary space and eventually to a spacecraft near the Earth. A set of seven simple particle events is studied, where energetic electrons (30-500 keV; Wind spacecraft) or protons (5-55 MeV; SoHO) were released together with low-energy electron beams producing metric-to-kilometric type III emission. Imaging of the coronal (metre-wave) part of this emission with the Nançay Radioheliograph is used to identify the open flux tubes that guide these electrons -and by inference all particles detected at 1 AU. Open coronal field lines are also computed using potential magnetic field extrapolations, constrained by a source surface and by SoHO/MDI measurements in the photosphere (code by Schrijver and DeRosa). We find that in all events the type III radio sources lie in open flux tubes in the potential magnetic field extrapolations. The open flux tubes are rooted in small parts of the parent active region, covering a heliocentric angle of a few degrees in the photosphere. But they expand rapidly above the neighbouring closed magnetic structures and cover several tens of degrees in longitude on the source surface. Some of these open field lines are found to connect the parent active region to the footpoint of the nominal Parker spiral on the source surface, within the uncertainty of about ±10• inherent to the evaluation of its connection longitude. This is so even when the parent active region is as far as 50• away. In two cases where the coronal flux tubes point to high heliolatitudes, the detection of Langmuir waves at the Wind spacecraft in the ecliptic plane suggests that the interplanetary field lines curve down to the ecliptic before reaching 1 AU. We conclude that non-radial open flux tubes in the corona can transport particles over several tens of degrees in longitude even in simple impulsive particle events. In all events we studied, potential magnetic field models give an adequate description of these structures.

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Cited by 48 publications

References 4 publications

Interplanetary Type IV Bursts

Interplanetary Type IV Bursts

On the relationship of shock waves to flares and coronal mass ejections

Open magnetic flux tubes in the corona and the transport of solar energetic particles

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