Pinch Sheets and Reconnection in Astrophysics

Сыроватский, С. И.

doi:10.1146/annurev.aa.19.090181.001115

Cited by 329 publications

(180 citation statements)

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“…This system has a more complex topology than that of Plate 1, it consists of four flux As a result of this expansion the null point in the corona deforms into a neutral sheet, similar to the process originally proposed by Syrovatskii (1981). Eventually, this neutral sheet becomes sufficiently thin that reconnection begins.…”

Section: Numerical Resultsmentioning

confidence: 62%

The role of magnetic reconnection in solar activity

Antiochos¹,

DeVore²

1999

Geophysical Monograph Series

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Abstract. We argue that magnetic reconnection plays the determining role in many of the various manifestations of solar activity. In particular, it is the trigger mechanism for the most energetic of solar events, coronal mass ejections and eruptive flares. We propose that in order to obtain explosive eruptions, magnetic reconnection in the corona must have an "on-off" nature, and show that reconnection in a sheared multi-polar field configuration does have this property. Numerical simulation results which support this model are presented, and implications for coronal mass ejections/eruptive flare prediction are discussed.

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Section: Numerical Resultsmentioning

confidence: 62%

The role of magnetic reconnection in solar activity

Antiochos¹,

DeVore²

1999

Geophysical Monograph Series

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“…Equation (22) provides us with only one LCE since we have only considered a single tangent vectorũ 0 . We can extend this definition by considering the LCEs of order 6 which describe the mean rate of growth of a 6-dimensional volume i.e., a parallelepiped whose edges correspond to the set of 6 linearly independent vectors U 0 ¼1 u 1 ; …;ũ 6 , thus the LCEs of order 6…”

Section: A Calculating the Complete Lyapunov Spectrummentioning

confidence: 99%

“…4,5 The null points of a magnetic field vector are important locations where strong currents can be found. 6 Strong currents play an important role in energy release processes such as magnetic reconnection where a change in the magnetic field topology could release energy to the surrounding plasma. This energy exchange is sometimes accompanied by rapid acceleration of charged particles due to the strong magnetic field-aligned electric fields present (see, for example, Refs.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of charged particle motion in the vicinity of three dimensional magnetic null points: Energization and chaos

Gascoyne

2015

Physics of Plasmas

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Using a full orbit test particle approach, we analyse the motion of a single proton in the vicinity of magnetic null point configurations which are solutions to the kinematic, steady state, resistive magnetohydrodynamics equations. We consider two magnetic configurations, namely, the sheared and torsional spine reconnection regimes [E. R. Priest and D. I. Pontin, Phys. Plasmas 16, 122101 (2009); P. Wyper and R. Jain, Phys. Plasmas 17, 092902 (2010)]; each produce an associated electric field and thus the possibility of accelerating charged particles to high energy levels, i.e., > MeV, as observed in solar flares [R. P. Lin, Space Sci. Rev. 124, 233 (2006)]. The particle's energy gain is strongly dependent on the location of injection and is characterised by the angle of approach b, with optimum angle of approach b opt as the value of b which produces the maximum energy gain. We examine the topological features of each regime and analyse the effect on the energy gain of the proton. We also calculate the complete Lyapunov spectrum for the considered dynamical systems in order to correctly quantify the chaotic nature of the particle orbits. We find that the sheared model is a good candidate for the acceleration of particles, and for increased shear, we expect a larger population to be accelerated to higher energy levels. In the strong electric field regime (E 0 ¼ 1500 V/m), the torsional model produces chaotic particle orbits quantified by the calculation of multiple positive Lyapunov exponents in the spectrum, whereas the sheared model produces chaotic orbits only in the neighbourhood of the null point. V C 2015 AIP Publishing LLC.

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“…It is widely believed [e.g., Syrovatskii, 1981] that solar flares draw their energy from the annihilation of magnetic fields. The rapid energy deposition following the annihilation should be an important source of turbulence and shocks.…”

Section: Introductionmentioning

confidence: 99%