Non-LTE Calculation of the N[CLC]i[/CLC] [CSC]i[/CSC] 676.8 Nanometer Line in a Flaring Atmosphere

Ding, M. D.; Qiu, Jiong; Wang, Haimin

doi:10.1086/343103

Cited by 46 publications

(49 citation statements)

References 15 publications

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“…Some 30 min after that, the measured field strengths stabilized at values significantly different than before the pulse. The impulsive change of the MDI magnetic field signal at 09:49-09:50 UT is an artifact, probably caused by the variation of the Ni i 6767.8 Å line due to the bombardment of energetic electron beams (Ding et al 2002; for similar events see Liu et al 2005, and references therein). However, once the line profile stabilizes as the flare fades, the MDI measurements should be as good as they were before (Ph.…”

Section: Flare or Cme?mentioning

confidence: 98%

Multi-wavelength study of coronal waves associated with the CME-flare event of 3 November 2003

Vršnak¹,

Warmuth

Temmer

et al. 2006

A&A

111

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The large flare/CME event that occurred close to the west solar limb on 3 November 2003 launched a large-amplitude large-scale coronal wave that was observed in Hα and Fe xii 195 Å spectral lines, as well as in the soft X-ray and radio wavelength ranges. The wave also excited a complex decimeter-to-hectometer type II radio burst, revealing the formation of coronal shock(s). The back-extrapolation of the motion of coronal wave signatures and the type II burst sources distinctly marks the impulsive phase of the flare (the hard X-ray peak, drifting microwave burst, and the highest type III burst activity), favoring a flare-ignited wave scenario. On the other hand, comparison of the kinematics of the CME expansion with the propagation of the optical wave signatures and type II burst sources shows a severe discrepancy in the CME-driven scenario. However, the CME is quite likely associated with the formation of an upper-coronal shock revealed by the decameter-hectometer type II burst. Finally, some six minutes after the launch of the first coronal wave, another coronal disturbance was launched, exciting an independent (weak) decimeter-meter range type II burst. The back-extrapolation of this radio emission marks the revival of the hard X-ray burst, and since there was no CME counterpart, it was clearly ignited by the new energy release in the flare. Moreton waves and type II bursts are very closely related phenomena (e.g., Harvey et al. 1974;Klassen et al. 2000;Khan & Aurass 2002;Warmuth et al. 2004b), indicating the common nature of the underlying disturbance. The physical background of the relationship was explained by Uchida (1974): the coronal fast-mode MHD shock that propagates along "valleys of low Alfven velocity" excites type II bursts in the corona, whereas the Moreton wave is a "surface track" of the shock front propagation (cf., Uchida 1974, and references therein).Generally, the coronal large-amplitude MHD disturbance could be generated by flares as well as by CMEs, and quite likely, both types of processes happen . The excellent timing association of Moreton waves and type II bursts with the impulsive phase of associated flares (e.g., Harvey 1965;Švestka & Fritzova-Švestkova 1974;Vršnak et al. 1995;Vršnak 2001;Klassen et al. 1999Klassen et al. , 2003) strongly suggests that the waves are ignited by flares. This is also supported by a number of relatively well-defined correlations between various wave characteristics and the flare energy release characteristics (e.g.,Article published by EDP Sciences and available at http://www.edpsciences.org/aa or http://dx

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Section: Flare or Cme?mentioning

confidence: 98%

Multi-wavelength study of coronal waves associated with the CME-flare event of 3 November 2003

Vršnak¹,

Warmuth

Temmer

et al. 2006

A&A

111

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“…The GONG magnetograms therefore provide the magnetic sensitivity, high cadence, spatial resolution, and spatial and temporal coverage required for the study of magnetic field changes during flares. As with all magnetographs, the GONG measurements of the longitudinal magnetic field are sensitive to changes in the photospheric line profile during the intense heating phase of solar flares ( Ding et al 2002;Edelman et al 2004).…”

Section: Datamentioning

confidence: 99%

Longitudinal Magnetic Field Changes Accompanying Solar Flares

Sudol

Harvey

2005

ApJ

262

265

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We have used Global Oscillation Network Group (GONG) magnetograms to characterize the changes in the photospheric longitudinal magnetic field during 15 X-class solar flares. An abrupt, significant, and persistent change in the magnetic field occurred in at least one location within the flaring active region during each event. We have identified a total of 42 sites where such field changes occurred. At 75% of these sites, the magnetic field change occurred in less than 10 minutes. The absolute values of the field changes ranged between 30 and almost 300 G, the median being 90 G. Decreases in the measured field component were twice as frequent as increases. The field changes ranged between 1.4 and 20 times the rms noise of the observations. In all but one equivocal case, the field changes occurred after the start of the flare. In all cases, the field changes were permanent. At least two-thirds of the field changes occurred in the penumbrae of sunspots. During three events for which simultaneous Transition Region and Coronal Explorer (TRACE ) images are available, we have found excellent spatial and temporal correlation between the change in the magnetic field and an increase in brightness of the footpoints of flare ribbons, but not vice versa. Among many possible explanations for the observations, we favor one in which the magnetic field changes result from the penumbral field relaxing upward by reconnecting magnetic fields above the surface. One of the basic assumptions of flare theories is that the photospheric magnetic field does not change significantly during flares. These results suggest that this assumption needs to be re-examined.

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“…The chromospheric response to electron bombardment was studied from modeling of the hydrogen Balmer lines (Kasparova & Heinzel 2002), the Ca xix line (Gan & Li 2002), the Ni i line (Ding et al 2002a), the Ha and Ca ii lines (Ding et al 2002b), and the Hb line (Gu et al 2001).…”

Section: Thermal Flare Plasma Dynamicsmentioning

confidence: 99%

Astrophysics in 2002

Trimble

Aschwanden

2003

PUBL ASTRON SOC PAC

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ABSTRACT. This has been the Year of the Baryon. Some low temperature ones were seen at high redshift, some high temperature ones were seen at low redshift, and some cooling ones were (probably) reheated. Astronomers saw the back of the Sun (which is also made of baryons), a possible solution to the problem of ejection of material by Type II supernovae (in which neutrinos push out baryons), the production of R Coronae Borealis stars (previously-owned baryons), and perhaps found the missing satellite galaxies (whose failing is that they have no baryons). A few questions were left unanswered for next year, and an attempt is made to discuss these as well.

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Non-LTE Calculation of the N[CLC]i[/CLC] [CSC]i[/CSC] 676.8 Nanometer Line in a Flaring Atmosphere

Cited by 46 publications

References 15 publications

Multi-wavelength study of coronal waves associated with the CME-flare event of 3 November 2003

Multi-wavelength study of coronal waves associated with the CME-flare event of 3 November 2003

Longitudinal Magnetic Field Changes Accompanying Solar Flares

Astrophysics in 2002

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