A newly observed solar feature - Macrospicules in He II 304 A

Bohlin, J. D.; Vogel, S. N.; Purcell, J. D.; Sheeley, N. R.; Tousey, R.; Vanhoosier, M. E.

doi:10.1086/181794

Cited by 129 publications

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“…Macrospicules are spiky features extending from the limb, which were first observed in He ii λ304 images (Bohlin et al 1975). …”

Section: Introductionmentioning

confidence: 86%

Observations of a rotating macrospicule associated with an X-ray jet

Kamio¹,

Curdt²,

Teriaca³

et al. 2010

A&A

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Aims. We attempt to understand the driving mechanism of a macrospicule and its relationship with a coronal jet. Methods. We study the dynamics of a macrospicule and an associated coronal jet captured by multi-spacecraft observations. Doppler velocities in both the macrospicule and the coronal jet are determined by EIS and SUMER spectra. Their temporal evolution is studied using X-ray and He ii λ304 images.Results. A blueshift of −120 ± 15 km s −1 is detected on one side of the macrospicule, while a redshift of 50 ± 6 km s −1 is found at the base of the other side. The inclination angle of the macrospicule inferred from a stereoscopic analysis with STEREO suggests that the measured Doppler velocities can be attributed to a rotating motion of the macrospicule rather than a radial flow or an expansion. Conclusions. The macrospicule is driven by the unfolding motion of a twisted magnetic flux rope, while the associated X-ray jet is a radial outflow.

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“…Macrospicules are spiky features extending from the limb, which were first observed in He ii λ304 images (Bohlin et al 1975). …”

Section: Introductionmentioning

confidence: 86%

Observations of a rotating macrospicule associated with an X-ray jet

Kamio¹,

Curdt²,

Teriaca³

et al. 2010

A&A

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“…Macrospicules were discovered by Bohlin et al (1975) in He II 30.4 nm spectroheliograms of the slitless spectrograph S082A. They had lengths of up to 50 and lifetimes between 5 min and 40 min.…”

Section: Spicules and Macrospiculesmentioning

confidence: 99%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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In Part I of this review, the concepts of solar vacuum-ultraviolet (VUV) observations were outlined together with a discussion of the space instrumentation used for the investigations. A section on spectroradiometry provided some quantitative results on the solar VUV radiation without considering any details of the solar phenomena leading to the radiation. Here, in Part II, we present solar VUV observations over the last decades and their interpretations in terms of the plasma processes and the parameters of the solar atmosphere, with emphasis on the spatial and thermal structures of the chromosphere, transition region and corona of the quiet Sun. In addition, observations of active regions, solar flares and prominences are included as well as of small-scale events. Special sections are devoted to the elemental composition of the solar atmosphere and theoretical considerations on the heating of the corona and the generation of the solar wind.

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“…Typically, they reach heights of 7 to 40 Mm (10 -60 ) with the lifetimes ranging from 3 to 45 min (Bohlin et al 1975;Withbroe et al 1976), and attain maximum velocities from 70 to 140 km s −1 (Dere et al 1989;Karovska & Habbal 1994). Another distinguishing feature of macrospicules is that they are predominantly observed in coronal holes (Bohlin et al 1975;Wang 1998).…”

Section: Introductionmentioning

confidence: 99%

Plasma dynamics in solar macrospicules from high-cadence extreme-UV observations

Loboda

Богачев

2017

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Macrospicules are relatively large spicule-like formations found mainly over the polar coronal holes when observing in the transition region spectral lines. In this study, we took advantage of the two short series of observations in the He ii 304 Å line obtained by the TESIS solar observatory with a cadence of up to 3.5 s to study the dynamics of macrospicules in unprecedented detail. We used a one-dimensional hydrodynamic method based on the assumption of their axial symmetry and on a simple radiative transfer model to reconstruct the evolution of the internal velocity field of 18 macrospicules from this dataset. Besides the internal dynamics, we studied the motion of the apparent end points of the same 18 macrospicules and found 15 of them to follow parabolic trajectories with high precision which correspond closely to the obtained velocity fields. We found that in a clear, unperturbed case these macrospicules move with a constant deceleration inconsistent with a purely ballistic motion and have roughly the same velocity along their entire axis, with the obtained decelerations typically ranging from 160 to 230 m s −2 , and initial velocities from 80 to 130 km s −1 . We also found a propagating acoustic wave for one of the macrospicules and a clear linear correlation between the initial velocities of the macrospicules and their decelerations, which indicates that they may be driven by magneto-acoustic shocks. Finally, we inverted our previous method by taking velocities from the parabolic fits to give rough estimates of the percentage of mass lost by 12 of the macrospicules. We found that typically from 10 to 30% of their observed mass fades out of the line (presumably being heated to higher coronal temperatures) with three exceptions of 50% and one of 80%.

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A newly observed solar feature - Macrospicules in He II 304 A

Cited by 129 publications

References 0 publications

Observations of a rotating macrospicule associated with an X-ray jet

Observations of a rotating macrospicule associated with an X-ray jet

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

Plasma dynamics in solar macrospicules from high-cadence extreme-UV observations

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