Elemental Abundances and Post–Coronal Mass Ejection Current Sheet in a Very Hot Active Region

Ciaravella, A.; Raymond, J. C.; Li, J.; Reiser, P. A.; Gardner, L. D.; Ko, Yuan‐Kuen; Fineschi, Silvano

doi:10.1086/341473

Cited by 141 publications

(175 citation statements)

References 42 publications

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“…Because the timescale of reconnection is long compared to the timescale of the onset stage (Alfvén timescale), a long CS would be expected in the eruption even though reconnection is considered fast. The highest altitude flare loops reach and the distance that the rear part of the CME propagates during the typical eruptive event have indirectly confirmed the formation of the long CS (see discussions of Ciaravella et al 2002;Lin 2002;Ko et al 2003;Lin et al 2005).…”

Section: Have Convincingly Showed That Both the Reconnection Sites Comentioning

confidence: 82%

“…For the first time, identified the reconnection inflow above the top of the flare loop system, and Ciaravella et al (2002) provided spectroscopic evidence of the CME/flare CS by displaying a narrow and hot region between a CME and the associated flare. This region was at the position where the CS is presumably located (see also Fig.…”

Section: Have Convincingly Showed That Both the Reconnection Sites Comentioning

confidence: 97%

“…Using data from Yohkoh and SOHO, Švestka (1996), Švestka et al (1998), Hudson (1999), andMcKenzie (2000) studied behaviors of regions above the top of the flare loop system, and displayed typical characteristics of the reconnection region and revealed important information above the reconnection process. Ciaravella et al (2002) analyzed spectral data obtained from the Ultraviolet Coronagraph Spectrometer (UVCS; Kohl et al 1995) on SOHO for an eruption on 1998 March 23. This event developed a slow CME propagating at speed of 100 km s −1 when the CME core was at the heliocentrical distance (namely the distance measured from the center of the Sun) of 3.5 R , and it reached a speed of 180 km s −1 as the core was at 15 R .…”

Section: Identifications Of the Current Sheet In The Solar Eruptive Ementioning

confidence: 99%

“…At the time of the UVCS observation, the LASCO CME was much larger but similar in shape. From Ciaravella et al (2002) the slit when [Fe XVIII] and [Ca XIV] emission was detected, and the other three slits are shown for comparison. The narrow and bright region in [Fe XVIII] and [Ca XIV] emission is located below the CME observed by LASCO/C2, and above the flare loop system observed mainly in Si XI emission by EIT in 304 Å.…”

Section: Identifications Of the Current Sheet In The Solar Eruptive Ementioning

confidence: 99%

“…Figure 3 of Ciaravella et al (2002) shows LASCO C1 images in Fe XIV λ5302.42 taken at different times on 1998 March 23, and displays the evolution of the magnetic configuration in the event; Figs. 8 and 9 of Ciaravella et al (2002) reveal features of the resultant flare loop system seen in various wavelengths, respectively.…”

Section: Identifications Of the Current Sheet In The Solar Eruptive Ementioning

confidence: 99%

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Review on Current Sheets in CME Development: Theories and Observations

et al. 2015

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We introduce how the catastrophe model for solar eruptions predicted the formation and development of the long current sheet (CS) and how the observations were used to recognize the CS at the place where the CS is presumably located. Then, we discuss the direct measurement of the CS region thickness by studying the brightness distribution of the CS region at different wavelengths. The thickness ranges from 10 4 km to about 10 5 km at heights between 0.27 and 1.16 R from the solar surface. But the traditional theory indicates that the CS is as thin as the proton Larmor radius, which is of order tens of meters in the corona. We look into the huge difference in the thickness between observations and theoretical expectations. The possible impacts that affect measurements and results are studied, and physical causes leading to a thick CS region in which reconnection can still occur at a reasonably fast rate are analyzed. Studies in both theories and observations suggest that the difference between the true value and the apparent value of the CS thickness is not significant as long as the CS could be recognised in observations. We review observations that show complex structures and flows inside the CS region and present recent numerical modelling results on some aspects of these structures. Both observations and numerical experiments indicate that the downward reconnection outflows are usually slower than the upward ones in the same eruptive event. Numerical simulations show that the complex structure inside CS and its temporal behavior as a result of turbulence and the Petschek-type slow-mode shock could probably account for the thick CS and fast reconnection. But whether the CS itself is that thick still remains unknown since, for the time being, we cannot measure the electric current directly in that region. We also review the most recent laboratory experiments of reconnection driven by energetic laser beams, and discuss some important topics for future works.

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Section: Have Convincingly Showed That Both the Reconnection Sites Comentioning

confidence: 82%

Section: Have Convincingly Showed That Both the Reconnection Sites Comentioning

confidence: 97%