CME Propagation Characteristics from Radio Observations

Pohjolainen, S.; Driel-Gesztelyi, L. van; Culhane, J. L.; Manoharan, P. K.; Elliott, H. A.

doi:10.1007/s11207-007-9006-6

Cited by 68 publications

(78 citation statements)

References 45 publications

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“…In spite of the lack of solar wind data in some of the events studied in this paper, the time of transit of all of them is well established:~17.5 h for C59 (Tsurutani et al 2003),~19 h for C03 (Skoug et al 2004) and~34 h for C05 (Pohjolainen et al 2007). A smaller transit time is equivalent to a larger solar wind velocity and therefore larger dynamical pressure will be expected.…”

Section: Discussionmentioning

confidence: 79%

Searching for Carrington-like events and their signatures and triggers

Sáiz

Guerrero

Cid

et al. 2016

J. Space Weather Space Clim.

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The Carrington storm in 1859 is considered to be the major geomagnetic disturbance related to solar activity. In a recent paper, Cid et al. (2015) discovered a geomagnetic disturbance case with a profile extraordinarily similar to the disturbance of the Carrington event at Colaba, but at a mid-latitude observatory, leading to a reinterpretation of the 1859 event. Based on those results, this paper performs a deep search for other ''Carrington-like'' events and analyses interplanetary observations leading to the ground disturbances which emerged from the systematic analysis. The results of this study based on two Carrington-like events (1) reinforce the awareness about the possibility of missing hazardous space weather events as the large H-spike recorded at Colaba by using global geomagnetic indices, (2) argue against the role of the ring current as the major current involved in Carrington-like events, leaving field-aligned currents (FACs) as the main current involved and (3) propose abrupt southward reversals of IMF along with high solar wind pressure as the interplanetary trigger of a Carrington-like event.

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Section: Discussionmentioning

confidence: 79%

Searching for Carrington-like events and their signatures and triggers

Sáiz

Guerrero

Cid

et al. 2016

J. Space Weather Space Clim.

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“…The establishment of a correspondence between frequency of observation-coronal height and frequency drift rate-radial speed is affected by ambiguities introduced by the variation of the ambient medium properties. These may be the result of the burst exciter propagation within undisturbed plasma, over-dense or under-dense structure or CME afterflows (see Pohjolainen et al, 2007;Pohjolainen, Hori, and Sakurai, 2008, for a detailed discussion on model selection). The density model of Vršnak, Magdalenić, and Zlobec (2004).…”

Section: Coronal Density-height Model 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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“…In this case, the calculation of the speed of the shock using the frequency-drift rate of the type II provides only a lower limit to the true speed of the shock (e.g. Pohjolainen et al 2007). …”

Section: The 2000 March 2 Eventmentioning

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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CME Propagation Characteristics from Radio Observations

Cited by 68 publications

References 45 publications

Searching for Carrington-like events and their signatures and triggers

Searching for Carrington-like events and their signatures and triggers

Interplanetary Type IV Bursts

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

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