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Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, Steven

doi:10.1023/a:1005149929192

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…The former source is consistent with the outmoving plasmoids found by SOHO/LASCO (Sheeley et al, 1997;Wang et al, 1998), while the latter source is corroborated by the SOHO/UVCS measurements (Abbo et al, 2010) and consistent with the established inverse correlation of the flow tube expansion with the solar wind speed (Wang and Sheeley, 1990). However, even at solar minimum, this scenario remains to be complemented with the expected source of the SSWs from inside streamers, either via direct flow of the plasma from the magnetically open fields in streamer cores (Noci et al, 1997) or via the evaporation of plasmas from the magnetic arcades in streamer helmets (Suess et al, 1999, also Li et al, 2005. Besides, using the method of interplanetary scintillation (IPS) tomographic analysis, Kojima et al (1999) found that yet another SSW source is the unipolar regions in the vicinity of active regions (ARs).…”

Section: Introductionsupporting

confidence: 71%

Coronal Sources and In Situ Properties of the Solar Winds Sampled by ACE During 1999 – 2008

et al. 2015

Sol Phys

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We identify the coronal sources of the solar winds sampled by the ACE spacecraft during [1999][2000][2001][2002][2003][2004][2005][2006][2007][2008], and examine the in situ solar wind properties as a function of wind sources. The standard two-step mapping technique is adopted to establish the photospheric footpoints of the magnetic flux tubes along which the ACE winds flow. The footpoints are then placed in the context of EIT 284Å images and photospheric magnetograms, allowing us to categorize the sources into four groups: coronal holes (CHs), active regions (ARs), the quiet Sun (QS), and "Undefined". This practice also enables us to establish the response to solar activity of the fractions occupied by each kind of solar winds, and of their speeds and O 7+ /O 6+ ratios measured in situ. We find that during the maximum phase, the majority of ACE winds originate from ARs. During the declining phase, CHs and ARs are equally important contributors to the ACE solar winds. The QS contribution increases with decreasing solar activity, and maximizes in the minimum phase when QS appear to be the primary supplier of the ACE winds. With decreasing activity, the winds from all sources tend to become cooler, as represented by the increasingly low O 7+ /O 6+ ratios. On the other hand, during each activity phase, the AR winds tend to be the slowest and associated with the highest O 7+ /O 6+ ratios, and the CH winds correspond to the other extreme, with the QS winds lying in between. Applying the same analysis method to the slow winds only, here defined as the winds with speeds lower than 500 km s −1 , we find basically the same overall behavior, as far as the contributions of individual groups of sources are concerned. This statistical study indicates that QS regions are an important source of the solar wind during the minimum phase.

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Section: Introductionsupporting

confidence: 71%

Coronal Sources and In Situ Properties of the Solar Winds Sampled by ACE During 1999 – 2008

et al. 2015

Sol Phys

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“…Secondly, for an oscillation period as small as, say, 30 minutes, the average phase speed is 965 km s −1 with a wavelength of 2.5 R ⊙ . As will be discussed in the discussion section of this paper, this means an Alfvén speed in the slow wind surrounding the plasma sheet significantly faster than that estimated from previous relevant theoretical calculations (e.g., Wang et al, 1998;Suess et al, 1999;Chen & Hu, 2001Hu et al, 2003;Li et al, 2006). According to these calculations, the plasma β should be no less than 0.1 in the slow wind regime surrounding the plasma sheet above the streamer cusp, this yields an Alfvén speed less than 575 km s −1 assuming an isothermal temperature of 1MK for both electrons and protons.…”

Section: Streamer Wave Analysismentioning

confidence: 82%

“…Regarding the solar wind conditions in the concerned region, the readers are referred to relevant observational studies (Sheeley et al, 1997;Wang et al, 2000;Strachan et al, 2002;Song et al, 2009) and theoretical modelings (e.g., Wang et al, 1998;Suess et al, 1999;Chen et al, 2001Chen et al, , 2002Hu et al, 2003;Li et al, 2006). In this short discussion, we simply make use of the solar wind conditions obtained by Chen & Hu (2001).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Streamer Waves Driven by Coronal Mass Ejections

Chen

Song

et al. 2010

ApJ

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Between July 5th and July 7th 2004, two intriguing fast coronal mass ejection(CME)-streamer interaction events were recorded by the Large Angle and Spectrometric Coronagraph (LASCO). At the beginning of the events, the streamer was pushed aside from their equilibrium position upon the impact of the rapidly outgoing and expanding ejecta; then, the streamer structure, mainly the bright streamer belt, exhibited elegant large scale sinusoidal wavelike motions. The motions were apparently driven by the restoring magnetic forces resulting from the CME impingement, suggestive of magnetohydrodynamic kink mode propagating outwards along the plasma sheet of the streamer. The mode is supported collectively by the streamer-plasma sheet structure and is therefore named " streamer wave" in the present study. With the white light coronagraph data, we show that the streamer wave has a period of about 1 hour, a wavelength varying from 2 to 4 solar radii, an amplitude of about a few tens of solar radii, and a propagating phase speed in the range 300 to 500 km s −1 . We also find that there is a tendancy for the phase speed to decline with increasing heliocentric distance. These observations provide good examples of large scale wave phenomena carried by coronal structures, and have significance in developing seismological techniques for diagnosing plasma and magnetic parameters in the outer corona.

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“…This process may release the closed-field plasma into the open field/solar wind (e.g., Fisk and Schwadron, 2001), or with complex coronal magnetic field topology with inversed polarity (separatrics) that favors magnetic reconnection and channel the accelerated plasma that ultimately is released into the open field lines expanding into the heliosphere (e.g., Antiochos et al, 2011;Titov et al, 2011). The third scenario (SSW3) is related to the weak magnetic field at the streamer cusp which makes it possible for the material in the underlying closed-field regions to be released into the solar wind through magnetic reconnection, diffusion or thermal instabilities (e.g., Suess et al, 1999;Einaudi et al, 1999). It should be noted that waves and turbulence can heat the plasma in closed magnetic field configurations as well, and this can provide the source of energy through thermal pressure that accelerates the plasma in closed field as it is injected into open field regions through the above reconnection scenarios.…”

Section: Which Are the Main Ssw Sources And Their Formation Mechanisms?mentioning

confidence: 99%

Slow Solar Wind: Observations and Modeling

et al. 2016

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While it is certain that the fast solar wind originates from coronal holes, where and how the slow solar wind (SSW) is formed remains an outstanding question in solar physics even in the post-SOHO era. The quest for the SSW origin forms a major objective for the planned future missions such as the Solar Orbiter and Solar Probe Plus. Nonetheless, results from spacecraft data, combined with theoretical modeling, have helped to investigate many aspects of the SSW. Fundamental physical properties of the coronal plasma have been derived from spectroscopic and imaging remote-sensing data and in situ data, and these results have provided crucial insights for a deeper understanding of the origin and acceleration of the SSW. Advanced models of the SSW in coronal streamers and other structures have been developed using 3D MHD and multi-fluid equations. However, the following questions remain open: What are the source regions and their contributions to the SSW? What is the role of the magnetic topology in the corona for the origin, acceleration and energy deposition of the SSW? What are the possible acceleration and heating mechanisms for the SSW? The aim of this review is to present insights on the SSW origin and formation gathered from the discussions at the International Space Science Institute (ISSI) by the Team entitled "Slow solar wind sources and acceleration mechanisms in the corona" held in Bern (Switzerland) in March 2014 and 2015.

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Untitled

Cited by 6 publications

References 7 publications

Coronal Sources and In Situ Properties of the Solar Winds Sampled by ACE During 1999 – 2008

Coronal Sources and In Situ Properties of the Solar Winds Sampled by ACE During 1999 – 2008

Streamer Waves Driven by Coronal Mass Ejections

Slow Solar Wind: Observations and Modeling

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