The relation between coronal holes and coronal mass ejections during the rise, maximum, and declining phases of Solar Cycle 23

Mohamed, Amaal Abd-Alla; Gopalswamy, Ν.; Yashiro, S.; Akiyama, S.; Mäkelä, P.; Xie, H.; Jung, H.

doi:10.1029/2011ja016589

Cited by 39 publications

(36 citation statements)

References 44 publications

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“…The idea is that the flux rope structure is not observed because the CME is deflected away from the Sun-Earth line so that the spacecraft at 1 AU crosses the flank of the corresponding ICME (see Gopalswamy, 2006). We compare the CH influence parameter obtained by Gopalswamy et al (2009) and Mohamed et al (2012) with the flux rope fitting results by Xie, Gopalswamy, and St. Cyr (2013). Xie, Gopalswamy, and St. Cyr (2013) found that on average the MC associated CMEs are deflected towards and the non-MC associated CMEs away from the Sun-Earth line.…”

Section: Introductionmentioning

confidence: 98%

Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

et al. 2013

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We report on the coronal hole (CH) influence on the 54 magnetic cloud (MC) and non-MC associated coronal mass ejections (CMEs) selected for studies during the Coordinated Data Analysis Workshops (CDAWs) focusing on the question if all CMEs are flux ropes. All selected CMEs originated from source regions located between longitudes 15E-15W. Xie, Gopalswamy, and St, Cyr (2013, Solar Phys., doi:10.1007/s11207-012-0209-0) found that these MC and non-MC associated CMEs are on average deflected towards and away from the Sun-Earth line respectively. We used a CH influence parameter (CHIP) that depends on the CH area, average magnetic field strength, and distance from the CME source region to describe the influence of all on-disk CHs on the erupting CME. We found that for CHIP values larger than 2.6 G the MC and non-MC events separate into two distinct groups where MCs (non-MCs) are deflected towards (away) from the disk center. Division into two groups was also observed when the distance to the nearest CH was less than 3.2x10^5 km. At CHIP values less than 2.6 G or at distances of the nearest CH larger than 3.2x10^5 km the deflection distributions of the MC and non-MCs started to overlap, indicating diminishing CH influence. These results give support to the idea that all CMEs are flux ropes, but those observed to be non-MCs at 1 AU could be deflected away from the Sun-Earth line by nearby CHs, making their flux rope structure unobservable at 1 AU.Comment: 19 pages, 4 figures; Solar Physics, 201

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Section: Introductionmentioning

confidence: 98%

Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

et al. 2013

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“…CME interactions can also result in CME deflection and merger (Shen et al 2012). In the declining phase, low-latitude coronal holes appear frequently, so CME deflection by such coronal holes becomes important (Gopalswamy et al 2009d;Mohamed et al 2012;Mäkelä et al 2013). The deflections are thought to be caused by the magnetic pressure gradient between the eruption region and the coronal hole (Gopalswamy et al 2010d;Shen et al 2011;Gui et al 2011).…”

Section: Propagation Effects: Deflection Interaction and Rotation Omentioning

confidence: 99%

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Gopalswamy

Tsurutani

Yan

2015

Prog. in Earth and Planet. Sci.

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This paper presents an overview of results obtained during the CAWSES-II period on the short-term variability of the Sun and how it affects the near-Earth space environment. CAWSES-II was planned to examine the behavior of the solar-terrestrial system as the solar activity climbed to its maximum phase in solar cycle 24. After a deep minimum following cycle 23, the Sun climbed to a very weak maximum in terms of the sunspot number in cycle 24 (MiniMax24), so many of the results presented here refer to this weak activity in comparison with cycle 23. The short-term variability that has immediate consequence to Earth and geospace manifests as solar eruptions from closed-field regions and high-speed streams from coronal holes. Both electromagnetic (flares) and mass emissions (coronal mass ejections -CMEs) are involved in solar eruptions, while coronal holes result in high-speed streams that collide with slow wind forming the so-called corotating interaction regions (CIRs). Fast CMEs affect Earth via leading shocks accelerating energetic particles and creating large geomagnetic storms. CIRs and their trailing high-speed streams (HSSs), on the other hand, are responsible for recurrent small geomagnetic storms and extended days of auroral zone activity, respectively. The latter leads to the acceleration of relativistic magnetospheric 'killer' electrons. One of the major consequences of the weak solar activity is the altered physical state of the heliosphere that has serious implications for the shock-driving and storm-causing properties of CMEs. Finally, a discussion is presented on extreme space weather events prompted by the 23 July 2012 super storm event that occurred on the backside of the Sun. Many of these studies were enabled by the simultaneous availability of remote sensing and in situ observations from multiple vantage points with respect to the Sun-Earth line.

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“…The importance of coronal holes for deflection is featured in many studies (e.g., . Gopalswamy et al (2009a) and Mohamed et al (2012) estimated the magnitude and direction of the resultant magnetic force exerted by all coronal holes present on the solar disk during the time of the CME eruption (defined as the CHIP parameter in Mohamed et al 2012) and compared this with CME trajectories and in situ observations. It was found that CMEs tend to move away from the coronal holes and the CMEs that erupt close to disk center but had large CHIP parameters produced generally complex ICMEs or driverless shocks in the near-Earth solar wind.…”

Section: Icmes and Magnetic Cloudsmentioning

confidence: 99%

The Physical Processes of CME/ICME Evolution

et al. 2017

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As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.

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The relation between coronal holes and coronal mass ejections during the rise, maximum, and declining phases of Solar Cycle 23

Cited by 39 publications

References 44 publications

Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

The Physical Processes of CME/ICME Evolution

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