Charge States and FIP Bias of the Solar Wind from Coronal Holes, Active Regions, and Quiet Sun

Fu, Hui; Madjarska, M. S.; Xia, Lidong; Li, Bo; Huang, Zhaoqin; Wangguan, Zhipeng

doi:10.3847/1538-4357/aa5cba

Cited by 31 publications

(36 citation statements)

References 70 publications

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“…Fe/O in the inverted HMF is significantly lower than in the slower wind behind, but is essentially the same as the faster wind ahead. For carbon and oxygen ion charge average states, the solar wind behind HMF inversions is significantly elevated relative to that ahead, as expected (Fu et al, 2017). Unlike the Fe/O, oxygen and carbon charge states in inverted HMF intervals are indistinguishable from the slower wind behind and significantly different from the faster wind ahead.…”

Section: Observations Of Inverted Hmfsupporting

confidence: 77%

Signatures of Coronal Loop Opening via Interchange Reconnection in the Slow Solar Wind at 1 AU

et al. 2020

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The opening of closed magnetic loops via reconnection with open solar flux, so called "interchange reconnection", is invoked in a number of models of slow solar wind release. In the heliosphere, this is expected to result in local switchbacks or inversions in heliospheric magnetic flux (HMF). When observed at 1 AU, inverted HMF has previously been shown to exhibit high ion charge states, suggestive of hot coronal loops, and to map to the locations of coronal magnetic separatrices. However, simulations show that inverted HMF produced directly by reconnection in the low corona is unlikely to survive to 1 AU without the amplification by solar wind speed shear. By considering the surrounding solar wind, we show that inverted HMF is preferably associated with regions of solar wind shear at 1 AU. Compared with the surrounding solar wind, inverted HMF intervals have lower magnetic field intensity and show intermediate speed and density values between the faster, more tenuous wind ahead and the slower, denser wind behind. There is no coherent signature in iron charge states, but oxygen and carbon charge states within the inverted HMF are in agreement with the higher values in the slow wind behind. Conversely, the iron-tooxygen abundance ratio is in better agreement with the lower values in the solar wind ahead, while the alpha-to-proton abundance ratio shows no variation. One possible explanation for these observations is that the interchange reconnection (and subsequent solar wind shear) that is responsible for generation of inverted HMF involves very small, quiet-Sun loops of approximately photospheric composition, which are impulsively heated in the low corona, rather than large-scale active region loops with enhanced first-ionisation potential elements. Whether signatures of such small loops could be detected in situ at 1 AU still remains to be determined.

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Section: Observations Of Inverted Hmfsupporting

confidence: 77%

Signatures of Coronal Loop Opening via Interchange Reconnection in the Slow Solar Wind at 1 AU

et al. 2020

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“…A host of studies have linked in situ solar wind observations to active region (AR) sources (Kojima et al 1999;Neugebauer et al 2002;Culhane et al 2014;Fazakerley et al 2016;Kilpua et al 2016;Fu et al 2017). Neugebauer et al (2002) found AR-associated SW to exhibit moderately lower speeds, higher charge states, and greater variability in composition and plasma parameters than those from CHs; similarly to the slow wind.…”

Section: Active Regions As Solar Wind Sourcesmentioning

confidence: 99%

Active Region Modulation of Coronal Hole Solar Wind

Macneil

Owen

Baker

et al. 2019

ApJ

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Active regions are a candidate source of the slow solar wind, the origins of which are a topic of ongoing research. We present a case study which examines the processes by which solar wind is modulated in the presence of an active region in the vicinity of the solar wind source. We compare properties of solar wind associated with a coronal hole-quiet Sun boundary, to solar wind associated with the same coronal hole, but one Carrington rotation later, when this region bordered the newly-emerged active region NOAA 12532. Differences found in a range of in situ parameters are compared between these rotations in the context of source region mapping and remote sensing observations. Marked changes exist in the structure and composition of the solar wind, which we attribute to the influence of the active region on solar wind production from the coronal hole boundary. These unique observations suggest that the features that emerge in the active region-associated wind are consistent with an increased occurrence of interchange reconnection during solar wind production, compared with the initial quiet Sun case.

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“…How the results change if the three types (CH, AR, and QS) solar wind are determined more restrictively? Usually the footpoints of the solar wind stay in a particular region for a few days (as shown in Figure 1 of Fu et al (2017)). A boundary wind is defined when the footpoint of the solar wind moves from one region to another (Neugebauer et al 2002).…”

Section: The Intervals Occupied By Interplanetary Coronal Mass Ejectimentioning

confidence: 99%

Helium abundance and speed difference between helium ions and protons in the solar wind from coronal holes, active regions, and quiet Sun

Madjarska

et al. 2018

Monthly Notices of the Royal Astronomical Society

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Two main models have been developed to explain the mechanisms of release, heating and acceleration of the nascent solar wind, the wave-turbulence-driven (WTD) models and reconnection-loop-opening (RLO) models, in which the plasma release processes are fundamentally different. Given that the statistical observational properties of helium ions produced in magnetically diverse solar regions could provide valuable information for the solar wind modelling, we examine the statistical properties of the helium abundance (A He ) and the speed difference between helium ions and protons (v αp ) for coronal holes (CHs), active regions (ARs) and the quiet Sun (QS). We find bimodal distributions in the space of A He and v αp /v A (where v A is the local Alfvén speed) for the solar wind as a whole. The CH wind measurements are concentrated at higher A He and v αp /v A values with a smaller A He distribution range, while the AR and QS wind is associated with lower A He and v αp /v A , and a larger A He distribution range. The magnetic diversity of the source regions and the physical processes related to it are possibly responsible for the different properties of A He and v αp /v A . The statistical results suggest that the two solar wind generation mechanisms, WTD and RLO, work in parallel in all solar wind source regions. In CH regions WTD plays a major role, whereas the RLO mechanism is more important in AR and QS. c 2018 The Authors 2 Hui Fu et al.

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Charge States and FIP Bias of the Solar Wind from Coronal Holes, Active Regions, and Quiet Sun

Cited by 31 publications

References 70 publications

Signatures of Coronal Loop Opening via Interchange Reconnection in the Slow Solar Wind at 1 AU

Signatures of Coronal Loop Opening via Interchange Reconnection in the Slow Solar Wind at 1 AU

Active Region Modulation of Coronal Hole Solar Wind

Helium abundance and speed difference between helium ions and protons in the solar wind from coronal holes, active regions, and quiet Sun

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