Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

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

doi:10.1007/s11207-012-0211-6

Cited by 55 publications

(46 citation statements)

References 32 publications

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“…However, there are many disk-center eruptions that are not observed as MCs. Propagation effects such as deflection in the corona (Xie, Gopalswamy and St. Cyr, 2013;Mäkelä et al, 2013) seem to be responsible for the non-cloud appearance of these events at 1 AU, even though there is no difference in the source properties of cloud and non-cloud ICMEs Yashiro et al, 2013). Therefore, it is possible to estimate the expected poloidal flux of the non-cloud ICMEs at 1 AU from the RC flux.…”

Section: Discussionmentioning

confidence: 99%

Estimation of Reconnection Flux Using Post-eruption Arcades and Its Relevance to Magnetic Clouds at 1 AU

et al. 2017

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We report on a new method to compute the flare reconnection (RC) flux from post-eruption arcades (PEAs) and the underlying photospheric magnetic fields. In previous works, the RC flux has been computed using cumulative flare ribbon area. Here we obtain the RC flux as half of that underlying the PEA associated with the eruption using an image in EUV taken after the flare maximum. We apply this method to a set of 21 eruptions that originated near the solar disk center in Solar Cycle 23. We find that the RC flux from the arcade method (ΦrA) has excellent agreement with that from the flare-ribbon method (ΦrR) according to: ΦrA = 1.24(ΦrR) 0.99 . We also find ΦrA to be correlated with the poloidal flux (ΦP) of the associated magnetic cloud at 1 AU: ΦP = 1.20(ΦrA) 0.85 . This relation is nearly identical to that obtained by Qiu et al. (Astrophys. J. 659, 758, 2007) using a set of only nine eruptions. Our result supports the idea that flare reconnection results in the formation of the flux rope and PEA as a common process.

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Section: Discussionmentioning

confidence: 99%

Estimation of Reconnection Flux Using Post-eruption Arcades and Its Relevance to Magnetic Clouds at 1 AU

et al. 2017

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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%

“…The empirical relationships established between HSS characteristics and the related geomagnetic activity provides an advance warning of impending CIR storms (Tsurutani et al 2006;Verbanac et al 2011). Coronal holes also deflect CME-driven shocks and CMEs that have important space weather consequences (Gopalswamy 2010(Gopalswamy , 2009dOlmedo et al 2012;Kay et al 2013;Mäkelä et al 2013). The deflection by coronal holes can be so large that CMEs originating from close the disk center of the Sun do not arrive at Earth while the shocks do.…”

Section: Coronal Holes and Cirsmentioning

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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“…This requires estimating the number of FRs expected from the observed number of CMEs. Recent studies conclude that a large fraction (Vourlidas et al, 2013) or even most of the CMEs Mäkelä et al, 2013) have a flux rope structure. The CMEs observed in-situ (ICMEs) without flux ropes would be cases crossed by the spacecraft close to the FR boundary, or even outside the FR (e.g.…”

Section: Are Mcs And/or Small Frs Related To Cmes?mentioning

confidence: 99%

Are There Different Populations of Flux Ropes in the Solar Wind?

2014

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Flux ropes are twisted magnetic structures, which can be detected by in-situ measurements in the solar wind. However, different properties of detected flux ropes suggest different types of flux-rope population. As such, are there different populations of flux ropes? The answer is positive, and is the result of the analysis of four lists of flux ropes, including magnetic clouds (MCs), observed at 1 AU. The in-situ data for the four lists have been fitted with the same cylindrical force-free model, which provides an estimation of the local flux-rope parameters such as its radius and orientation. Since the flux-rope distributions have a large dynamic range, we go beyond a simple histogram analysis by developing a partition technique that uniformly distributes the statistical fluctuations over the radius range. By doing so, we find that small flux ropes with radius R < 0.1 AU have a steep power-law distribution in contrast to the larger flux ropes (identified as MCs), which have a Gaussian-like distribution. Next, from four CME catalogs, we estimate the expected flux-rope frequency per year at 1 AU. We find that the predicted numbers are similar to the frequencies of MCs observed in-situ. However, we also find that small flux ropes are at least ten times too abundant to correspond to CMEs, even to narrow ones. Investigating the different possible scenarios for the origin of those small flux ropes, we conclude that these twisted structures can be formed by blowout jets in the low corona or in coronal streamers.

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Coronal Hole Influence on the Observed Structure of Interplanetary CMEs

Cited by 55 publications

References 32 publications

Estimation of Reconnection Flux Using Post-eruption Arcades and Its Relevance to Magnetic Clouds at 1 AU

Estimation of Reconnection Flux Using Post-eruption Arcades and Its Relevance to Magnetic Clouds at 1 AU

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

Are There Different Populations of Flux Ropes in the Solar Wind?

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