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Donea, Alina-Catalina; Lindsey, C.; Braun, D. C.

doi:10.1023/a:1005280327665

Cited by 44 publications

(47 citation statements)

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“…Comparing our observations with previous 2-d investigations of chromospheric dynamics they seem to contradict observed Ca II K power halos (Braun et al 1992;Toner & LaBonte 1993;Thomas & Stanchfield 2000). These power enhancements were also investigated using photospheric data from ground and from MDI (Thomas & Stanchfield 2000;Brown et al 1992;Hindman & Brown 1998;Donea et al 2000;Jain 2001;Jain & Haber 2002). In this case the intensity power maps show neither enhancement nor darkening around the sunspot.…”

Section: Discussionsupporting

confidence: 46%

“…They all found the same enhancements of high frequency power around the AR. Using lower temperature lines like Fe I (from ground) or Ni I (with MDI on SoHO) various groups searched for these features in the photosphere (Brown et al 1992;Hindman & Brown 1998;Thomas & Stanchfield 2000;Donea et al 2000;Jain 2001;Jain & Haber 2002). Power enhancements (also called power aureoles or halos) were present in 3 min velocity power maps.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of solar active regions

Muglach

2003

A&A

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Abstract. I present results of an international joint observing campaign, which was carried out in September 1999 and 2000, to study the oscillatory behaviour of active regions (ARs). In this contribution I will concentrate on oscillations in the higher layers of the solar atmosphere as observed with the UV filters of the Transition Region and Coronal Explorer (TRACE). I present the distribution of oscillatory power of two extended active regions. I find a number of well-known chromospheric dynamic phenomena such as running penumbral waves, enhanced 5 min power in the plage and network regions and additional 3 min power in the internetwork. In addition, I find that the 3 min power in the surroundings of the AR is decreased, an effect that has not been observed before. From the topology of the magnetic field I infer that this can be explained by an interaction of the acoustic wavefield with the expanding magnetic field of the active region.

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Section: Discussionsupporting

confidence: 46%

Section: Introductionmentioning

confidence: 99%

Dynamics of solar active regions

Muglach

2003

A&A

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“…is impulsive (Donea & Lindsey 2012;Sudol & Harvey 2005;Petrie & Sudol 2010). We therefore use the typical timescale of the hard X-ray spike, i.e., around 10 s, as a rough estimate of δt during the flare impulsive phase.…”

Section: Statistical Resultsmentioning

confidence: 99%

The Relationship Between the Sudden Change of the Lorentz Force and the Magnitude of Associated Flares

Wang¹,

Liu²,

Wang³

2012

ApJ

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The rapid and irreversible change of photospheric magnetic fields associated with flares has been confirmed by many recent studies. These studies showed that the photospheric magnetic fields respond to coronal field restructuring and turn to a more horizontal state near the magnetic polarity inversion line (PIL) after eruptions. Recent theoretical work has shown that the change in the Lorentz force associated with a magnetic eruption will lead to such a field configuration at the photosphere. The Helioseismic Magnetic Imager has been providing unprecedented full-disk vector magnetograms covering the rising phase of the solar cycle 24. In this study, we analyze 18 flares in four active regions, with GOES X-ray class ranging from C4.7 to X5.4. We find that there are permanent and rapid changes of magnetic field around the flaring PIL, the most notable of which is the increase of the transverse magnetic field. The changes of fields integrated over the area and the derived change of Lorentz force both show a strong correlation with flare magnitude. It is the first time that such magnetic field changes have been observed even for C-class flares. Furthermore, for seven events with associated coronal mass ejections (CMEs), we use an estimate of the impulse provided by the Lorentz force, plus the observed CME velocity, to estimate the CME mass. We find that if the timescale of the back reaction is short, i.e., in the order of 10 s, the derived values of CME mass (∼10 15 g) generally agree with those reported in literature.

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“…Hence, in order to test the helioseismic findings in this paper versus background seismic sources, we follow Donea et al (2000) and turn to the quiet Sun as the control exercise. We have extracted the quiet Sun data cube from Mauna Loa velocity observations.…”

Section: Appendix Helioseismology Control Exercise: Quiet Sunmentioning

confidence: 99%

ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG,HINODE, ANDRHESSI

Matthews

Zharkov

Zharkova

2011

ApJ

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Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its impact in the photosphere and the solar interior. Using data from Hinode, TRACE, RHESSI, and GONG we study the temporal and spatial evolution of the 2006 December 14 X-class flare in the chromosphere, photosphere, and the solar interior. We investigate the connections between the emission at various atmospheric depths, including acoustic signatures obtained by time-distance and holography methods from the GONG data. We report the horizontal displacements observed in the photosphere linked to the timing and locations of the acoustic signatures we believe to be associated with this flare, their vertical and horizontal displacement velocities, and their potential implications for current models of flare dynamics.

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Cited by 44 publications

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Dynamics of solar active regions

Dynamics of solar active regions

The Relationship Between the Sudden Change of the Lorentz Force and the Magnitude of Associated Flares

ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG,HINODE, ANDRHESSI

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