scholarly journals Study of the propagation, in situ signatures, and geoeffectiveness of shear-induced coronal mass ejections in different solar winds

Author(s):  
D.-C. Talpeanu ◽  
S. Poedts ◽  
E. D'Huys ◽  
M. Mierla
Solar Physics ◽  
2011 ◽  
Vol 276 (1-2) ◽  
pp. 293-314 ◽  
Author(s):  
T. Rollett ◽  
C. Möstl ◽  
M. Temmer ◽  
A. M. Veronig ◽  
C. J. Farrugia ◽  
...  

2002 ◽  
Vol 20 (7) ◽  
pp. 891-916 ◽  
Author(s):  
D. B. Berdichevsky ◽  
C. J. Farrugia ◽  
B. J. Thompson ◽  
R. P. Lepping ◽  
D. V. Reames ◽  
...  

Abstract. The extreme ultraviolet (EUV) signatures of a solar lift-off, decametric and kilometric radio burst emissions and energetic particle (EP) inner heliospheric signatures of an interplanetary shock, and in situ identification of its driver through solar wind observations are discussed for 12 isolated halo coronal mass ejections (H-CMEs) occurring between December 1996 and 1997. For the aforementioned twelve and the one event added in the discussion, it is found that ten passed several necessary conditions for being a "Sun-Earth connection". It is found that low corona EUV and Ha chromospheric signatures indicate filament eruption as the cause of H-CME. These signatures indicate that the 12 events can be divided into two major subsets, 7 related to active regions (ARs) and 5 unrelated or related to decayed AR. In the case of events related to AR, there is indication of a faster lift-off, while a more gradual lift-off appears to characterize the second set. Inner heliospheric signatures – the presence of long lasting enhanced energetic particle flux and/or kilometric type II radio bursts – of a driven shock were identified in half of the 12 events. The in situ (1 AU) analyses using five different solar wind ejecta signatures and comparisons with the bidirectional flow of suprathermal particles and Forbush decreases result in indications of a strong solar wind ejecta signatures for 11 out of 12 cases. From the discussion of these results, combined with work by other authors for overlapping events, we conclude that good Sun-Earth connection candidates originate most likely from solar filament eruptions with at least one of its extremities located closer to the central meridian than ~ 30° E or ~ 35° W with a larger extension in latitudinal location possible. In seven of the twelve cases it appears that the encountered ejecta was driving a shock at 1 AU. Support for this interpretation is found on the approximately equal velocity of the shock and the ejecta leading-edge. These shocks were weak to moderate in strength, and a comparison of their transit time with their local speed indicated a deceleration. In contradistinction with this result on shocks, the transit time versus the local speed of the ejecta appeared either to indicate that the ejecta as a whole traveled at constant speed or underwent a small amount of acceleration. This is a result that stands for cases with and without fast stream observations at their rear end. Seven out of twelve ejecta candidate intervals were themselves interplanetary magnetic cloud (IMC) or contained a previously identified IMC. As a by-product of this study, we noticed two good ejecta candidates at 1 AU for which observation of a H-CME or CME appears to be missing.Key words. Radio science (remote sensing); Solar physics, astrophysics and astronomy (flares and mass ejections); Space plasma physics (nonlinear phenomena)


Solar Physics ◽  
2011 ◽  
Vol 270 (2) ◽  
pp. 561-573 ◽  
Author(s):  
L. Rodriguez ◽  
M. Mierla ◽  
A. N. Zhukov ◽  
M. West ◽  
E. Kilpua

2020 ◽  
Vol 904 (2) ◽  
pp. 177
Author(s):  
Tarik M. Salman ◽  
Noé Lugaz ◽  
Charles J. Farrugia ◽  
Reka M. Winslow ◽  
Lan K. Jian ◽  
...  

2020 ◽  
Vol 493 (1) ◽  
pp. L16-L21 ◽  
Author(s):  
Anil N Raghav ◽  
Zubair I Shaikh

ABSTRACT The interplanetary counterparts of coronal mass ejections (ICMEs) are the leading driver of severe space weather. Their morphological evolution in interplanetary space and the prediction of their arrival time at Earth are the ultimate focus of space weather studies, because of their scientific and technological effects. Several investigations in the last couple of decades have assumed that ICMEs have a circular cross-section. Moreover, various models have also been developed to understand the morphology of ICMEs based on their deformed cross-section. In fact, simulation studies have suggested that the initial circular cross-section flattens significantly during their propagation in the solar wind and this is referred to as ‘pancaking’. However, an observational verification of this phenmenon is still pending and it will eventually be the primary concern of several morphological models. Here, we report the first unambiguous observational evidence of extreme flattening of the cross-section of ICMEs, similar to pancaking, based on in situ measurements of 30 ICME events. In fact, we conclude that the cross-section of ICME flux ropes transformed into a two-dimensional planar magnetic structure. Such a deformed morphological feature not only alters the prediction of their arrival time but also has significant implications in solar-terrestrial physics, the energy budget of the heliosphere, charged particle energization, turbulence dissipation and enhanced geo-effectiveness, etc.


2011 ◽  
Vol 7 (S286) ◽  
pp. 149-153
Author(s):  
Hebe Cremades ◽  
Cristina H. Mandrini ◽  
Sergio Dasso

AbstractWe have investigated two full solar rotations belonging to two distinct solar minima, in the frame of two coordinated observational and research campaigns. The nearly uninterrupted gathering of solar coronal data since the beginning of the SOHO era offers the exceptional possibility of comparing two solar minima for the first time, with regard to coronal transients. This study characterizes the variety of outward-travelling transients observed in the solar corona during both time intervals, from very narrow jet-like events to coronal mass ejections (CMEs). Their solar source regions and ensuing interplanetary structures were identified and characterized. Multi-wavelength images from the space missions SOHO, Yohkoh and STEREO, and ground-based observatories were studied for coronal ejecta and their solar sources, while in situ data registered by the ACE spacecraft were inspected for interplanetary CMEs and magnetic clouds. Instrumental aspects such as dissimilar resolution, cadence, and fields of view are considered in order to discern instrumentally-driven disparities from inherent differences between solar minima.


2020 ◽  
Author(s):  
Yutian Chi ◽  
Chris Scott ◽  
Chenglong Shen ◽  
Yuming Wang

<div> <div> <div>Coronal mass ejections (CME) are large-scale eruptions of magnetized plasma and huge energy through the corona and out into interplanetary space. <div>A mount of CMEs observed by HI-1 cameras present two fronts that are similar in shape but separated by a few degrees in elongation. Scott et al. (2019) interpret the ghost fronts as projections of separate discrete sections of the physical boundary of the  CME. Ghost fronts could provide information about the longitudinal shape of CME in the field of view of Hi- 1, which can be used to improve the forecast of the arrival time of ICME. During 13-15 June 2012, STEREO/SECCHI recorded two successive launched Earth-directed CMEs. Both of the two CMEs show clearly two fronts in HI-1 images. We use the ghost fronts to predict the arrival time of the two CMEs and utility the in-situ measurements from VEX and Wind to verify the accuracy of the prediction of ghost fronts model. </div> </div> </div> </div>


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