The association of coronal mass ejections with their effects near the Earth

By R. Schwenn, A. Lago, E. Huttunen, W. Gonzalez. 2005

383 citations recorded by the source corpus.

Abstract. To this day, the prediction of space weather effects near the Earth suffers from a fundamental problem: The radial propagation speed of "halo" CMEs (i.e. CMEs pointed along the Sun-Earth-line that are known to be the main drivers of space weather disturbances) towards the Earth cannot be measured directly because of the unfavorable geometry. From inspecting many limb CMEs observed by the LASCO coronagraphs on SOHO we found that there is usually a good correlation between the radial speed and the lateral expansion speed Vexp of CME clouds. This latter quantity can also be determined for earthward-pointed halo CMEs. Thus, Vexp may serve as a proxy for the otherwise inaccessible radial speed of halo CMEs. We studied this connection using data from both ends: solar data and interplanetary data obtained near the Earth, for a period from January 1997 to 15 April 2001. The data were primarily provided by the LASCO coronagraphs, plus additional information from the EIT instrument on SOHO. Solar wind data from the plasma instruments on the SOHO, ACE and Wind spacecraft were used to identify the arrivals of ICME signatures. Here, we use "ICME" as a generic term for all CME effects in interplanetary space, thus comprising not only ejecta themselves but also shocks as well. Among 181 front side or limb full or partial halo CMEs recorded by LASCO, on the one hand, and 187 ICME events registered near the Earth, on the other hand, we found 91 cases where CMEs were uniquely associated with ICME signatures in front of the Earth. Eighty ICMEs were associated with a shock, and for 75 of them both the halo expansion speed Vexp and the travel time Ttr of the shock could be determined. The function Ttr=203-20.77*ln (Vexp) fits the data best. This empirical formula can be used for predicting further ICME arrivals, with a 95% error margin of about one day. Note, though, that in 15% of comparable cases, a full or partial halo CME does not cause any ICME signature at Earth at all; every fourth partial halo CME and every sixth limb halo CME does not hit the Earth (false alarms). Furthermore, every fifth transient shock or ICME or isolated geomagnetic storm is not caused by an identifiable partial or full halo CME on the front side (missing alarms).

Subfields: Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/e45d028af14913f94017e6e9d13f4adea5a94ebe

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In Astronomy and Astrophysics

1. M. Temmer
2. N. Lugaz
3. T. Howard
4. B. Vršnak
5. A. Vourlidas
6. R. Schwenn
7. Nat Gopalswamy
8. C. Farrugia

In Molecular Biology

1. M. Temmer
2. N. Lugaz
3. J. Davies
4. T. Howard
5. B. Vršnak
6. Jan Luhmann
7. C. Farrugia
8. S. Patsourakos

Citations in the corpus

• Geoeffective Properties of Solar Transients and Stream Interaction Regions (2017, background): “We now know that intense and sporadic magnetic storms are caused mostly by CMEs (e.g., Webb et al. 2000; Schwenn et al. 2005), although prior to their identification in 1970s with space-borne coronagraphs (Tousey 1973; Gosling et al. 1975), solar flares were thought to be the responsible drivers.”
• NO TRACE LEFT BEHIND: STEREO OBSERVATION OF A CORONAL MASS EJECTION WITHOUT LOW CORONAL SIGNATURES (2009, methodology): “Schwenn et al. (2005) reported that about 20% of the geoeffective ICMEs were not preceded by an identifiable frontside halo CME (they used SOHO/EIT data to separate backsided CMEs).”
• Properties and geoeffectiveness of magnetic clouds in the rising, maximum and early declining phases of solar cycle 23 (2005, methodology): “The method to determine the expansion speed is described in dal Lago et al. (2003) and Schwenn et al. (2005).”
• CONNECTING SPEEDS, DIRECTIONS AND ARRIVAL TIMES OF 22 CORONAL MASS EJECTIONS FROM THE SUN TO 1 AU (2014, methodology): “Similar relationships have been shown for example by Schwenn et al. (2005) and Vršnak & Žic (2007), but using CME coronagraph speeds, whereas we show interplanetary speeds.”
• Properties of Interplanetary Coronal Mass Ejections (2007, background): “Schwenn et al. (2005) have suggested a way to avoid the projection effects.”
• Space Weather: The Solar Perspective (2006, background): “But the scatter was found to be similarly large even in ideal cases when both the true radial CME speed and the travel times to an in situ observer can precisely be determined (Schwenn et al., 2005).”
• Interplanetary Coronal Mass Ejections Observed in the Heliosphere: 1. Review of Theory (2009, background): “It is generally accepted that ICMEs are responsible for the majority of severe geomagnetic storms observed at Earth (e.g., Burlaga et al. 1981; Gosling 1993; Schwenn et al. 2005 and references therein) and thus understanding the propagation of ICMEs is vital to the forecasting of such events.”
• The Physical Processes of CME/ICME Evolution (2017, methodology): “A similar plot is presented in Vršnak and Žic (2007), and for additional examples see also Manoharan et al. (2004), Schwenn et al. (2005), Manoharan and Mujiber Rahman (2011).”
• S/WAVES: The Radio and Plasma Wave Investigation on the STEREO Mission (2008, neutral): “6.2 (Gopalswamy et al. 2001b; Schwenn et al. 2005).”