Magnetic reconnection and energy release on the Sun and solar-like stars

Driel‐Gesztelyi, L. van

doi:10.1017/s1743921309030440

Cited by 3 publications

(7 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ultimately, we are left with the question: what caused the coherent gyrophase bunching in these energetic electron distributions? Torbert et al (2018) and Egedal et al (2019) both determined that this reconnection event observed by MMS on July 11, 2017 was consistent with 2-dimensional, symmetric, antiparallel reconnection, which is important since it indicates that the fields around the EDR in question were coherently structured and not dominated by turbulent fluctuations (e.g., Figure 2o from Torbert et al [2018] and Figure 2 from Egedal et al [2019]). J.…”

Section: Discussionmentioning

confidence: 66%

“…Only FEEPS data from MMS-1, -2, and -3 are shown and discussed here due to limitations from sunlight contamination in FEEPS on MMS-4. As reported by Torbert et al (2018), the X-line was oriented such that the L-, M-, and N-directions (Denton et al, 2018) were approximately parallel to X-, Y-, Z-GSE directions, and the reconnection involved a weak guide field (|B M |/|B L | ∼4%; note also that the guide field was estimated as even weaker, ∼0.6%, by Egedal et al [2019]). When observed by MMS, the X-line was receding tailward (i.e., in the negative X-GSE direction) at approximately 170 km/s.…”

Section: Data Observations and Analysismentioning

confidence: 60%

“…On July 11, 2017 MMS encountered an EDR at approximately 22:34:03 UT, and after the encounter, MMS observed the Earthward exhaust of the active reconnection site (Torbert et al, 2018). We examined that case in detail from an energetic electron perspective using burst-resolution data from the fluxgate magnetometer (Russell et al, 2016) and Fly's Eye Energetic Particle Spectrometer (FEEPS) (Blake et al, 2016) instruments from all four spacecraft.…”

Section: Data Observations and Analysismentioning

confidence: 99%

See 2 more Smart Citations

Characteristics of Energetic Electrons Near Active Magnetotail Reconnection Sites: Tracers of a Complex Magnetic Topology and Evidence of Localized Acceleration

Turner

Cohen

Bingham

et al. 2021

Geophysical Research Letters

View full text Add to dashboard Cite

Magnetic reconnection is a fundamental physical process affecting plasmas from laboratory experiments to astrophysical environments (Hesse & Cassak, 2020; Zweibel & Yamada, 2009). Reconnection involves the explosive reconfiguration of magnetic field topologies, in which two previously unconnected field lines break apart and reconnect to each other. The reconnection itself takes place at very small scales, corresponding to thermal electron kinetic scales (e.g., several to ∼10 s of km in Earth's magnetosphere [Burch & Phan, 2016]), in a location referred to as the electron diffusion region (EDR) that lies at the intersection of an "X-line" in the magnetic topology (by "topology" we mean an instantaneous snapshot of the time-varying, 3-dimensional spatial configuration of magnetic field-lines). During reconnection, which is an energy conversion process in plasma physics, energy stored in the magnetic field is transferred to the particles in the plasma. That energy transfer results in kinetic motion manifested as outflow jets from the reconnection site, plasma heating, and acceleration of suprathermal energetic particles. The electron-scale physics and microscopic nature of reconnection have recently been illuminated in unprecedented detail by NASA'

show abstract

Section: Discussionmentioning

confidence: 66%

Section: Data Observations and Analysismentioning

confidence: 60%

Section: Data Observations and Analysismentioning

confidence: 99%

See 1 more Smart Citation

Characteristics of Energetic Electrons Near Active Magnetotail Reconnection Sites: Tracers of a Complex Magnetic Topology and Evidence of Localized Acceleration

Turner

Cohen

Bingham

et al. 2021

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…For the eruption to occur, the magnetic balance must be disrupted in favor of the upward-directed pressure force. Discussions of ideas for eruption onset mechanisms are presented in detail in several works and reviews, including van Driel-Gesztelyi et al (2002); Klimchuk (2001); Linker et al (2003); Forbes et al (2006); Moore & Sterling (2006); van Driel-Gesztelyi (2009). Recently the consensus is that a "storage and release of energy" process occurs, where possible methods to release the energy are numerous.…”

Section: Introductionmentioning

confidence: 99%

Evidence for magnetic flux cancelation leading to an ejective solar eruption observed byHinode,TRACE,STEREO, andSoHO/MDI

Sterling¹,

Chifor²,

Mason³

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. We study the onset of a solar eruption involving a filament ejection on 2007 May 20. Methods. We observe the filament in Hα images from Hinode/SOT and in EUV with TRACE and STEREO/SECCHI/EUVI. Hinode/XRT images are used to study the eruption in soft X-rays. From spectroscopic data taken with Hinode/EIS we obtain bulkflow velocities, line profiles, and plasma densities in the onset region. The magnetic field evolution was observed in SoHO/MDI magnetograms. Results. We observed a converging motion between two opposite polarity sunspots that form the primary magnetic polarity inversion line (PIL), along which resides filament material before eruption. Positive-flux magnetic elements, perhaps moving magnetic features (MMFs) flowing from the spot region, appear north of the spots, and the eruption onset occurs where these features cancel repeatedly in a negative-polarity region north of the sunspots. An ejection of material observed in Hα and EUV marks the start of the filament eruption (its "fast-rise"). The start of the ejection is accompanied by a sudden brightening across the PIL at the jet's base, observed in both broad-band images and in EIS. Small-scale transient brightenings covering a wide temperature range (Log T e = 4.8−6.3) are also observed in the onset region prior to eruption. The preflare transient brightenings are characterized by sudden, localized density enhancements (to above Log n e [cm −3 ] = 9.75, in Fe xiii) that appear along the PIL during a time when pre-flare brightenings were occurring. The measured densities in the eruption onset region outside the times of those enhancements decrease with temperature.Persistent downflows (red-shifts) and line-broadening (Fe xii) are present along the PIL.Conclusions. The array of observations is consistent with the pre-eruption sheared-core magnetic field being gradually destabilized by evolutionary tether-cutting flux cancelation that was driven by converging photospheric flows, and the main filament ejection being triggered by flux cancelation between the positive flux elements and the surrounding negative field. A definitive statement however on the eruption's ultimate cause would require comparison with simulations, or additional detailed observations of other eruptions occurring in similar magnetic circumstances.

show abstract

“…In spite of the large number of studies of these processes, carried out by both data analyses (van Driel-Gesztelyi 2002;Zuccarello et al 2009) and numerical simulations (Cheung et al 2008, and references therein), several aspects remain unclear. For instance, it remains unclear the role played by the so-called moving magnetic features (MMFs, hereafter), small magnetic-flux concentrations, which are usually observed streaming out from the sunspot penumbra, later interacting with the ambient magnetic field, and then disappearing (Sheeley 1969;Harvey & Harvey 1973).…”

Section: Introductionmentioning

confidence: 99%

Observation of bipolar moving magnetic features streaming out from a naked spot

Zuccarello¹,

Romano

Guglielmino³

et al. 2009

A&A

View full text Add to dashboard Cite

Context. Mechanisms responsible for active-region formation, evolution, and decay have been investigated by many authors and several common features have been identified. In particular, a key element in the dispersal of the magnetic field seems to be the presence of magnetic elements, called moving magnetic features (MMFs). Aims. We analyze the short-lived sunspot group NOAA 10977, which appeared on the solar disk between 2 and 8 December 2007, to study the details of its emergence and decay phases.Methods. We performed a multi wavelength analysis of the region using images at visible (G band and H α ) and near-IR (Ca ii) wavelengths acquired by both the IBIS instrument and SOT/HINODE, EUV images (17.1 nm) acquired by TRACE, and MDI and SOT magnetograms. Results. The observed region exhibits some peculiarities. During the emergence phase the formation of the f-pore was initially observed, while the p-polarity later formed a naked spot, i.e., a sunspot without a penumbra. We measured a moat flow around this spot, and observed some MMFs streaming out from it during the decay phase. The characteristics of these MMFs allowed us to classify them as type I (U-shaped) MMFs. They were also cospatial with sites of increased brightness both in the photosphere and the chromosphere. Conclusions. The presence of bipolar MMFs in a naked spot indicates that current interpretation of bipolar MMFs, as extensions of the penumbral filaments beyond the sunspot outer boundaries, should be revised, to take into account this observational evidence. We believe that our results provide new insights into improving models of sunspot evolution.

show abstract

Magnetic reconnection and energy release on the Sun and solar-like stars

Cited by 3 publications

References 44 publications

Characteristics of Energetic Electrons Near Active Magnetotail Reconnection Sites: Tracers of a Complex Magnetic Topology and Evidence of Localized Acceleration

Characteristics of Energetic Electrons Near Active Magnetotail Reconnection Sites: Tracers of a Complex Magnetic Topology and Evidence of Localized Acceleration

Evidence for magnetic flux cancelation leading to an ejective solar eruption observed byHinode,TRACE,STEREO, andSoHO/MDI

Observation of bipolar moving magnetic features streaming out from a naked spot

Contact Info

Product

Resources

About