A Study of Flare‐associated X‐Ray Plasma Ejections. III. Kinematic Properties

This paper outlines the current understanding of solar flares, mainly focused on magnetohydrodynamic (MHD) processes responsible for producing a flare. Observations show that flares are one of the most explosive phenomena in the atmosphere of the Sun, releasing a huge amount of energy up to about 10 32 erg on the timescale of hours. Flares involve the heating of plasma, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes for producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), local enhancement of electric current in the corona (formation of a current sheet), and rapid dissipation of electric current (magnetic reconnection) that causes shock heating, mass ejection, and particle acceleration. The evolution toward the onset of a flare is rather quasi-static when free energy is accumulated in the form of coronal electric current (field-aligned current, more precisely), while the dissipation of coronal current proceeds rapidly, producing various dynamic events that affect lower atmospheres such as the chromosphere and photosphere. Flares manifest such rapid dissipation of coronal current, and their theoretical modeling has been developed in accordance with observations, in which numerical simulations proved to be a strong tool reproducing the time-dependent, nonlinear evolution of a flare. We review the models proposed to explain the physical mechanism of flares, giving an comprehensive explanation of the key processes mentioned above. We start with basic properties of flares, then go into the details of energy build-up, release and transport in flares where magnetic reconnection works as the central engine to produce a flare.

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“…2 Tsuneta (1996). 3 , , Kim et al (2005). 4 McKenzie and ), McKenzie (2000, Innes et al (2003), Sui and Holman (2003).…”

Section: Avalanche Model and Non-reconnection Modelsmentioning

confidence: 99%

“…7 Wang et al (2007). 8 Shibata et al (1995), Tsuneta (1997), Shibata (1997, 1998), Kim et al (2005). 9 Asai et al (2004), Linton and Longcope (2006), TanDokoro and Fujimoto (2005).…”

Section: Avalanche Model and Non-reconnection Modelsmentioning

confidence: 99%

Solar Flares: Magnetohydrodynamic Processes

Shibata

Magara

2011

Living Rev. Solar Phys.

746

647

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“…Since plasmoid ejections have been observed in both longduration events and compact flares (e.g., Shibata et al 1995), the magnetic reconnection model may be applicable even for compact flares, which often do not show the other typical features of magnetic reconnection, such as particle acceleration or loop-top source. For example, in the soft X-ray image, upward-moving blobs of hot plasma have often been observed (Shibata et al 1995;Ohyama & Shibata 1998;Kim et al 2005) and Hα observations supplemented with TRACE 171 Å data have provided evidence for the formation of plasma blob (Srivastava et al 2012). Moreover, the white-light coronagraph observations in the near-Sun region have also recorded rising blob-like features in the wake of CMEs (Ko et al 2003;Lin et al 2005).…”

Section: Introductionmentioning

confidence: 98%

Eruption of a plasma blob, associated M-class flare, and large-scale extreme-ultraviolet wave observed by SDO

Kumar

Manoharan

2013

A&A

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We present a multiwavelength study of the formation and ejection of a plasma blob and associated extreme ultraviolet (EUV) waves in active region (AR) NOAA 11176, observed by SDO/AIA and STEREO on 25 March 2011. The EUV images observed with the AIA instrument clearly show the formation and ejection of a plasma blob from the lower atmosphere of the Sun at ∼9 min prior to the onset of the M1.0 flare. This onset of the M-class flare happened at the site of the blob formation, while the blob was rising in a parabolic path with an average speed of ∼300 km s −1 . The blob also showed twisting and de-twisting motion in the lower corona, and the blob speed varied from ∼10−540 km s −1 . The faster and slower EUV wavefronts were observed in front of the plasma blob during its impulsive acceleration phase. The faster EUV wave propagated with a speed of ∼785 to 1020 km s −1 , whereas the slower wavefront speed varied in between ∼245 and 465 km s −1 . The timing and speed of the faster wave match the shock speed estimated from the drift rate of the associated type II radio burst. The faster wave experiences a reflection by the nearby AR NOAA 11177. In addition, secondary waves were observed (only in the 171 Å channel), when the primary fast wave and plasma blob impacted the funnel-shaped coronal loops. The Helioseismic Magnetic Imager (HMI) magnetograms revealed the continuous emergence of new magnetic flux along with shear flows at the site of the blob formation. It is inferred that the emergence of twisted magnetic fields in the form of arch-filaments/"anemone-type" loops is the likely cause for the plasma blob formation and associated eruption along with the triggering of M-class flare. Furthermore, the faster EUV wave formed ahead of the blob shows the signature of fast-mode MHD wave, whereas the slower wave seems to be generated by the field line compression by the plasma blob. The secondary wave trains originated from the funnel-shaped loops are probably the fast magnetoacoustic waves.

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“…However, X-ray plasmoids generally do not represent the early signature of a CME's leading edge but sometimes just form by tearing of the current sheet in the course of the flaring process beneath the CME (Shibata & Tanuma 2001), so various types of relations were observed (for details see Kim et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Acceleration in Fast Halo CMEs and Synchronized Flare HXR Bursts

Temmer

Veronig

Vršnak

et al. 2008

ApJ

202

167

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We study two well-observed, fast halo CMEs, covering the full CME kinematics including the initiation and impulsive acceleration phase, and their associated flares. We find a close synchronization between the CME acceleration profile and the flare energy release as indicated by the RHESSI hard X-ray flux onsets, as well as peaks occur simultaneously within 5 minutes. These findings indicate a close physical connection between both phenomena and are interpreted in terms of a feedback relationship between the CME dynamics and the reconnection process in the current sheet beneath the CME.

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A Study of Flare‐associated X‐Ray Plasma Ejections. III. Kinematic Properties

Cited by 19 publications

References 44 publications

Solar Flares: Magnetohydrodynamic Processes

Solar Flares: Magnetohydrodynamic Processes

Eruption of a plasma blob, associated M-class flare, and large-scale extreme-ultraviolet wave observed by SDO

Acceleration in Fast Halo CMEs and Synchronized Flare HXR Bursts

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