Predicted Light Curves for a Model of Solar Eruptions

Reeves, Katharine K.; Forbes, T. G.

doi:10.1086/432047

Cited by 39 publications

(51 citation statements)

References 38 publications

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“…The ratio between both magnetic powers is more than two orders of magnitude. Under the assumption that the same ratio holds for SXR emissions (which is not trivial since it depends on the reconnection rate, see Reeves & Forbes 2005), our scalings are consistent with relatively older (resp. younger) ARs producing C-class (resp.…”

Section: Energetics and Time-scalessupporting

confidence: 71%

“…Several 2.5D MHD simulations for flares and CME early phases have calculated the magnetic and thermal properties of this standard model (e.g. Amari et al 1996;Chen & Shibata 2000;Linker et al 2003;Reeves & Forbes 2005;Shiota et al 2005;Jacobs et al 2006). They confirmed the cartoons, and successfully explained many observed properties.…”

Section: Introductionmentioning

confidence: 65%

“…These discrepencies may be related to the efficiency of magnetic energy conversion into flare emissions, during magnetic reconnection. While this aspect is not treated in our zero-β simulation, Reeves & Forbes (2005) have indeed shown that all things being equal, the faster the reconnection takes place, the smaller the fraction of magnetic energy is converted into thermal energy, hence into flare emissions. The associated time-scales for the flare readily fit those measured for weakly and highly energetic flares (Sect.…”

Section: Energetics and Time-scalesmentioning

confidence: 92%

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The standard flare model in three dimensions

Aulanier¹,

Janvier²,

Schmieder³

2012

A&A

262

267

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Context. The standard CSHKP model for eruptive flares is two-dimensional. Yet observational interpretations of photospheric currents in pre-eruptive sigmoids, shear in post-flare loops, and relative positioning and shapes of flare ribbons, all together require threedimensional extensions to the model. Aims. We focus on the strong-to-weak shear transition in post-flare loops, and on the time-evolution of the geometry of photospheric electric currents, which occur during the development of eruptive flares. The objective is to understand the three-dimensional physical processes, which cause them, and to know how much the post-flare and the pre-eruptive distributions of shear depend on each other. Methods. The strong-to-weak shear transition in post-flare loops is identified and quantified in a flare observed by STEREO, as well as in a magnetohydrodynamic simulation of CME initiation performed with the OHM code. In both approaches, the magnetic shear is evaluated with field line footpoints. In the simulation, the shear is also estimated from ratios between magnetic field components. Results. The modeled strong-to-weak shear transition in post-flare loops comes from two effects. Firstly, a reconnection-driven transfer of the differential magnetic shear, from the pre-to the post-eruptive configuration. Secondly, a vertical straightening of the inner legs of the CME, which induces an outer shear weakening. The model also predicts the occurrence of narrow electric current layers inside J-shaped flare ribbons, which are dominated by direct currents. Finally, the simulation naturally accounts for energetics and time-scales for weak and strong flares, when typical scalings for young and decaying solar active regions are applied. Conclusions. The results provide three-dimensional extensions to the standard flare model. These extensions involve MHD processes that should be tested with observations.

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Section: Energetics and Time-scalessupporting

confidence: 71%

Section: Introductionmentioning

confidence: 65%

Section: Energetics and Time-scalesmentioning

confidence: 92%

See 1 more Smart Citation

The standard flare model in three dimensions

Aulanier¹,

Janvier²,

Schmieder³

2012

A&A

262

267

View full text Add to dashboard Cite

show abstract

“…The CME velocityḣ that is deduced by integrating equations (2)Y(5) with the initial conditions given in equations (7) could be an upper limit, since we treat the CME as a projectile in our calculations (e.g., , and all the magnetic energy released is assumed to be used in speeding up the CME. Recently, Reeves & Forbes (2005) studied the heating features associated with CME motions and found that including the thermal energy and evaporation in the catastrophe model does not change our previous results because only the work done by the magnetic force on the flux rope affects the trajectories.…”

Section: Various Components Of Cme Speedsmentioning

confidence: 74%

Theoretical Investigation of the Onsets of Type II Radio Bursts during Solar Eruptions

Lin

Mancuso

Vourlidas

2006

ApJ

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On the basis of previous works, we investigated coronal mass ejection (CME) propagations and the consequent type II radio bursts invoked by the CME-driven shocks. The results indicate that the onset of type II bursts depends on the local Alfvén speed (or the magnetoacoustic wave speed in the nonYforce-free environment), which is governed by both the magnetic field and the plasma density. This determines that the type II burst cannot appear at any altitude. Instead, its onset positions can never be lower than a critical height for the given coronal environment, which consequently determines the start frequencies of the emission: for an eruption taking place in the magnetic configuration with a background field of 100 G, the onset of type II bursts should occur at around 0.5 R from the solar surface, and the corresponding start frequency of the fundamental component is about 150 MHz. This result is consistent with similar estimates based on observations that bring the corresponding frequency to a few hundred MHz. Our results further indicate that the onset of type II bursts depends on the rate of magnetic reconnection as well. When magnetic reconnection during the eruption is not fast enough, a type II burst may not occur at all even if the associated CME is fast (say, faster than 800 km s À1 ). This may account for the fast and radio-quiet CMEs. Related to these results, properties of the associated solar flares and type III radio bursts, especially those used as the precursors of the type II radio bursts, are also discussed.

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“…Because of the gap in SXT observations, we cannot rule out the possibility that the flare site was behind the limb and thus partially occulted. However, as shown most recently by Aarnio et al (2010), it is possible to have powerful and massive CMEs associated with relatively weak flares (see also Reeves & Forbes 2005). (Scherrer et al 1995) takes high spectral resolution images of the Ni i λ6768 absorption line to characterize velocity oscillations and Zeeman splitting in the photosphere.…”

Section: Yohkoh/sxt Observationsmentioning

confidence: 90%

PLASMA HEATING DURING A CORONAL MASS EJECTION OBSERVED BY THESOLAR AND HELIOSPHERIC OBSERVATORY

Murphy

Raymond

Korreck

2011

ApJ

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We perform a time-dependent ionization analysis to constrain plasma heating requirements during a fast partial halo coronal mass ejection (CME) observed on 2000 June 28 by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO). We use two methods to derive densities from the UVCS measurements, including a density sensitive O v line ratio at 1213.85 and 1218.35 Å, and radiative pumping of the O vi λλ1032, 1038 doublet by chromospheric emission lines. The most strongly constrained feature shows cumulative plasma heating comparable to or greater than the kinetic energy, while features observed earlier during the event show plasma heating of order or less than the kinetic energy. SOHO Michelson Doppler Imager observations are used to estimate the active region magnetic energy. We consider candidate plasma heating mechanisms and provide constraints when possible. Because this CME was associated with a relatively weak flare, the contribution from flare energy (e.g., through thermal conduction or energetic particles) is probably small; however, the flare may have been partially behind the limb. Wave heating by photospheric motions requires heating rates to be significantly larger than those previously inferred for coronal holes, but the eruption itself could drive waves that heat the plasma. Heating by small-scale reconnection in the flux rope or by the CME current sheet is not significantly constrained. UVCS line widths suggest that turbulence must be replenished continually and dissipated on timescales shorter than the propagation time in order to be an intermediate step in CME heating.

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Predicted Light Curves for a Model of Solar Eruptions

Cited by 39 publications

References 38 publications

The standard flare model in three dimensions

The standard flare model in three dimensions

Theoretical Investigation of the Onsets of Type II Radio Bursts during Solar Eruptions

PLASMA HEATING DURING A CORONAL MASS EJECTION OBSERVED BY THESOLAR AND HELIOSPHERIC OBSERVATORY

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