Photometric study of chromospheric and coronal spikes observed during the total solar eclipse of 30 June, 1973

Koutchmy, S.; Stellmacher, G.

doi:10.1007/bf00162449

Cited by 35 publications

(14 citation statements)

References 11 publications

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“…A careful inspection of the original images reveals a large number of super-fine features that are about or slightly less than 1 arcsec across, i.e., about 700 km. Such fine spatial resolution has so far been reported only by Nesmyanovich et al (1974) from observations of the eclipse in 1968 by a telescope, whose focal length was 10 m, and by Vsekhsvjatsky et al (1970) and November & Koutchmy (1996), who went even below 1 arcsec thanks to excellent observing conditions and the use of a powerful 3.6 m Canada-France-Hawaii telescope in Hawai (see also Koutchmy & Stellmacher 1976;and Koutchmy et al 1994). Apart from well-known loops at the bases of helmet streamers and radial or slightly bent rays and plumes, our pictures also reveal a number of bright and dark structures of a helical shape, which to the best of our knowledge are reported for the first time.…”

Section: Discussionmentioning

confidence: 95%

Comparing eclipse observations of the 2008 August 1 solar corona with an MHD model prediction

Rusin¹,

Druckmüller

Aniol³

et al. 2010

A&A

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Context. The structure of the white-light and emission solar coronas and their MHD modelling are the context of our work. Aims. A comparison is made between the structure of the solar corona as observed during the 2008 August 1 total eclipse from Mongolia and that predicted by an MHD model. Methods. The model has an improved energy formulation, including the effect of coronal heating, conduction of heat parallel to the magnetic field, radiative losses, and acceleration by Alfvén waves. Results. The white-light corona, which was visible up to 20 solar radii, was of an intermediate type with well-pronounced helmet streamers situated above a chain of prominences at position angles of 48, 130, 241, and 322 degrees. Two polar coronal holes, filled with a plethora of thin polar plumes, were observed. High-quality pictures of the green (530.3 nm, Fe XIV) corona were obtained with the help of two narrow-passband filters (centered at the line itself and the vicinity of 529.1 nm background), with a FWHM of 0.15 nm. Conclusions. The large-scale shape of both the white-light and green corona was found to agree well with that predicted by the model. In this paper we describe the morphological properties of the observed corona, and how it compares with that predicted by the model. A more detailed analysis of the quantitative properties of the corona will be addressed in a future publication.

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Section: Discussionmentioning

confidence: 95%

Comparing eclipse observations of the 2008 August 1 solar corona with an MHD model prediction

Rusin¹,

Druckmüller

Aniol³

et al. 2010

A&A

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“…The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instrument package on the pair of NASA STEREO spacecraft images the slow solar wind during the final stages of its acceleration. The morphology of streamers is quite well understood experimentally (Koutchmy & Stellmacher 1976;Schmahl et al 1992) and by means of numerical modeling (Mikić & Linker 1996;Wang et al 1997;Mikić et al 2000;Saez et al 2000;Thernisien & Howard 2006). Streamers are usually constrained to low heliocentric latitudes at solar minimum (McComas et al 1998) but broaden and can form at high latitudes during solar maximum (McComas et al 2001;Balogh & Smith 2001).…”

Section: Introductionmentioning

confidence: 95%

Slow Magnetoacoustic Wave Oscillation of an Expanding Coronal Loop

Schmidt

Ofman

2011

ApJ

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We simulated an expanding loop or slow coronal mass ejection (CME) in the solar corona dimensioned with size parameters taken from real coronal expanding loops observed with the STEREO spacecraft. We find that the loop expands to Sun's size within about one hour, consistent with slow CME observations. At the top of the loop, plasma is being blown off the loop, enabled with the reconnection between the loop's flux rope magnetic field and the radial magnetic field of the Sun, thus yielding feeding material for the formation of the slow solar wind. This mechanism is in accordance with the observed blob formation of the slow solar wind. We find wave packets traveling with local sound speed downward toward the footpoints of the loop, already seen in coronal seismology observations and simulations of stationary coronal loops. Here, we generalize these results for an expanding medium. We also find a reflection of the wave packets, identified as slow magnetoacoustic waves, at the footpoints of the loop. This confirms the formation of standing waves within the coronal loop. In particular, the reflected waves can partly escape the loop top and contribute to the heating of the solar wind. The present study improves our understanding on how loop material can emerge to form blobs, major ingredients of slow CMEs, and how the release of the wave energy stored in slow magnetoacoustic waves, and transported away from the Sun within expanding loops, contributes to the acceleration and formation of the slow solar wind.

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“…Probably, it is just a question of terminology used by different authors. In any case, these structures can be seen quite high in the corona sometimes extending from the tops of macrospicules (Brueckner, 1980) and may be related to H e material moving to heights of as much as 10 R o (Sheeley et al, 1981) and coronal spikes seen in white light during eclipse by Koutchmy and Stellmacher (1976). It has been interpreted (Brueckner, 1980;Brueckner and Bartoe, 1983) that some events originate as small exploding loops.…”

Section: Outward Mass Motions As Seen In the Euvmentioning

confidence: 99%

Driving mechanisms for the solar wind

Pneuman

1986

Space Sci Rev

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In this review, we consider the central physical aspects pertinent to the acceleration of the solar wind. Special importance is placed on the high-speed streams since the properties of these structures seem to strain the various theoretical explanations the most. Heavy emphasis is also given to the observations -particularly as to what constraints they place on the theories. We also discuss certain sporadic events such as spicules, macrospicules, X-ray bright points, and outflows seen in the EUV associated with the explosive events, jets, and coronal bullets which could be of relevance to this problem.Three theoretical concepts pertaining to the solar wind acceleration process are examined -purely thermal acceleration with and without extended heating, acceleration due to Alfvrn wave pressure, and diamagnetic acceleration. Emphasis is given to how well these theories meet the constraints imposed by the observations. Diamagnetism is argued to be a powerful ingredient in solar wind theory, both in the light of observed sporatic outflows seen in the chromosphere and transition region and also because of its effectiveness in increasing the flow speed and producing strong acceleration near the Sun in line with coronal hole observations.

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Photometric study of chromospheric and coronal spikes observed during the total solar eclipse of 30 June, 1973

Cited by 35 publications

References 11 publications

Comparing eclipse observations of the 2008 August 1 solar corona with an MHD model prediction

Comparing eclipse observations of the 2008 August 1 solar corona with an MHD model prediction

Slow Magnetoacoustic Wave Oscillation of an Expanding Coronal Loop

Driving mechanisms for the solar wind

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