Distribution of jets and magnetic fields in a coronal hole

Kamio, S.; Hara, Hirohisa; Watanabe, Tetsuya; Curdt, W.

doi:10.1051/0004-6361/200811125

Cited by 19 publications

(15 citation statements)

References 38 publications

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“…It is proposed that the cool plasma flow is driven by the magnetic tension force and pressure of reconnected fields and the reconnection accelerates the faster jet component of the event. Kamio et al (2009) infer that low-lying fields can lead to reconnection in the transition region which results in cool upflows or explosive events and the lack of a coronal counterpart is due to a closed field configuration. A schematic picture of the configuration of this process (which strongly agrees with our observation of Jet 2) is presented in Kamio et al (2009, Figure 10).…”

Section: Cool Loop Eventmentioning

confidence: 99%

“…Kamio et al (2009) infer that low-lying fields can lead to reconnection in the transition region which results in cool upflows or explosive events and the lack of a coronal counterpart is due to a closed field configuration. A schematic picture of the configuration of this process (which strongly agrees with our observation of Jet 2) is presented in Kamio et al (2009, Figure 10). Yokoyama & Shibata (1995) previously showed that a cool jet is formed alongside a hot jet.…”

Section: Cool Loop Eventmentioning

confidence: 99%

“…We expect that the dark strand observed in Jet 2 reveals the presence of a cool loop with two footpoints which are identified by the blue followed by redshifted plasma. Cool upflows have been identified from EIS (He ii and O iv emission) and SUMER (Ne viii) data which occur in network regions harboring low-lying fields in the transition region (Kamio et al 2009). They suggested that these flows are produced by an acceleration of plasma in the chromosphere which propagate into the transition region.…”

Section: Cool Loop Eventmentioning

confidence: 99%

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Jets in Polar Coronal Holes

Scullion

Popescu

Banerjee

et al. 2009

ApJ

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Here, we explore the nature of small-scale jet-like structures and their possible relation to explosive events and other known transient features, like spicules and macrospicules, using high-resolution spectroscopy obtained with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurements of Emitted Radiation instrument. We present a highly resolved spectroscopic analysis and line parameter study of time-series data for jets occurring on-disk and off-limb in both a northern and a southern coronal hole. The analysis reveals many small-scale transients which rapidly propagate between the mid-transition region (N iv 765 Å line formation: 140,000 K) and the lower corona (Ne viii 770 Å line formation: 630,000 K). In one example, a strong jet-like event is associated with a cool feature not present in the Ne viii 770 Å line radiance or Doppler velocity maps. Another similar event is observed, but with a hot component, which could be perceived as a blinker. Our data reveal fast, repetitive plasma outflows with blueshift velocities of ≈145 km s −1 in the lower solar atmosphere. The data suggest a strong role for smaller jets (spicules), as a precursor to macrospicule formation, which may have a common origin with explosive events.

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Section: Cool Loop Eventmentioning

confidence: 99%

Section: Cool Loop Eventmentioning

confidence: 99%

Section: Cool Loop Eventmentioning

confidence: 99%

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Jets in Polar Coronal Holes

Scullion

Popescu

Banerjee

et al. 2009

ApJ

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“…Using spectroscopic data from SOHO/SUMER and Hinode/EIS, Kamio et al (2009) investigated the formation of jets in the transition region and coronal environment of CHs. They deduced that the open magnetic fields associated with the jets were rooted in kG vertical fields at photospheric levels.…”

Section: Polar Jetsmentioning

confidence: 99%

The magnetic field in the solar atmosphere

Wiegelmann

Thalmann

Solanki

2014

Astron Astrophys Rev

183

125

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This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.

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“…As for EIS, the Doppler shift is deduced after compensating for the instrumental effect caused by temperature variations (Kamio et al 2010b) and using the rest wavelengths of emission lines identified by Brown et al (2008). The contribution of the Si x λ25.637 nm blending in the He ii λ25.632 nm is subtracted by using the other Si x λ26.106 nm emission (Kamio et al 2009). Although a coronal blending remains in the red wing of the spectrum, He ii is the dominant emission at that wavelength.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Evolution of microflares associated with bright points in coronal holes and in quiet regions

Kamio

Curdt

Teriaca

et al. 2011

A&A

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Aims. We aim to find similarities and differences between microflares at coronal bright points found in quiet regions and coronal holes, and to study their relationship with large scale flares. Methods. Coronal bright points in quiet regions and in coronal holes were observed with Hinode/EIS using the same sequence. Microflares associated with bright points are identified from the X-ray lightcurve. The temporal variation of physical properties was traced in the course of microflares.Results. The lightcurves of microflares indicated an impulsive peak at hot emission followed by an enhancement at cool emission, which is compatible with the cooling model of flare loops. The density was found to increase at the rise of the impulsive peak, supporting chromospheric evaporation models. A notable difference is found in the surroundings of microflares; diffuse coronal jets are produced above microflares in coronal holes while coronal dimmings are formed in quiet regions. Conclusions. The microflares associated with bright points share common characteristics to active region flares. The difference in the surroundings of microflares are caused by open and closed configurations of the pre-existing magnetic field.

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Distribution of jets and magnetic fields in a coronal hole

Cited by 19 publications

References 38 publications

Jets in Polar Coronal Holes

Jets in Polar Coronal Holes

The magnetic field in the solar atmosphere

Evolution of microflares associated with bright points in coronal holes and in quiet regions

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