Acceleration of charged particles in magnetic reconnection: Solar flares, the magnetosphere, and solar wind

Goldstein, M. L.; Matthaeus, W. H.; Ambrosiano, John

doi:10.1029/gl013i003p00205

Cited by 46 publications

(24 citation statements)

References 17 publications

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“…This phenomenon has also been considered as a potential mechanism to accelerate charged particles (electrons and ions) in a broad variety of astrophysical contexts, in particular, in the solar corona. [5][6][7][8][9][10] During a solar flare event, a large number of charged particles is accelerated which can reach energies far beyond the mean thermal velocity of the solar corona. RHESSI observations have provided a rich source of data on the processes of particle acceleration in the solar corona.…”

Section: Introductionmentioning

confidence: 99%

Comparison of test particle acceleration in torsional spine and fan reconnection regimes

2014

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Magnetic reconnection is a common phenomenon taking place in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. Torsional spine and fan reconnections are important mechanisms proposed for steady-state three-dimensional nullpoint reconnection. By using the magnetic and electric fields for these regimes, we numerically investigate the features of test particle acceleration in both regimes with input parameters for the solar corona. By comparison, torsional spine reconnection is found to be more efficient than torsional fan reconnection in an acceleration of a proton to a high kinetic energy. A proton can gain as high as 100 MeV of relativistic kinetic energy within only a few milliseconds. Moreover, in torsional spine reconnection, an accelerated particle can escape either along the spine axis or on the fan plane depending on its injection position. However, in torsional fan reconnection, the particle is only allowed to accelerate along the spine axis. In addition, in both regimes, the particle's trajectory and final kinetic energy depend on the injection position but adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory. V C 2014 AIP Publishing LLC. [http://dx.

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Section: Introductionmentioning

confidence: 99%

Comparison of test particle acceleration in torsional spine and fan reconnection regimes

2014

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“…In general in a turbulent collisionless plasma the bandwidth of the inertial range fluctuations may extend from large fluctuations at the correlation scale, λ c , to small fluctuations at the ion inertial scale. In this case β ≫ 1 and the turbulent time-scales are much slower than the typical particle gyroradius [25]. The resonant condition for the static case in terms of β is given by…”

Section: Model and Governing Equationsmentioning

confidence: 99%

Magnetic moment nonconservation in magnetohydrodynamic turbulence models

et al. 2012

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The fundamental assumptions of the adiabatic theory do not apply in presence of sharp field gradients as well as in presence of well developed magnetohydrodynamic turbulence. For this reason in such conditions the magnetic moment µ is no longer expected to be constant. This can influence particle acceleration and have considerable implications in many astrophysical problems.Starting with the resonant interaction between ions and a single parallel propagating electromagnetic wave, we derive expressions for the magnetic moment trapping width ∆µ (defined as the half peak-to-peak difference in the particle magnetic moment) and the bounce frequency ω b . We perform test-particle simulations to investigate magnetic moment behavior when resonances overlapping occurs and during the interaction of a ring-beam particle distribution with a broad-band slab spectrum.We find that magnetic moment dynamics is strictly related to pitch angle α for a low level of magnetic fluctuation, δB/B0 = (10 −3 , 10 −2 ), where B0 is the constant and uniform background magnetic field. Stochasticity arises for intermediate fluctuation values and its effect on pitch angle is the isotropization of the distribution function f (α). This is a transient regime during which magnetic moment distribution f (µ) exhibits a characteristic one-sided long tail and starts to be influenced by the onset of spatial parallel diffusion, i.e., the variance (∆z) 2 grows linearly in time as in normal diffusion. With strong fluctuations f (α) isotropizes completely, spatial diffusion sets in and f (µ) behavior is closely related to the sampling of the varying magnetic field associated with that spatial diffusion.

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“…Eventually, MHD can be combined with kinetic studies to quantify the overall dissipation over both inertial and dissipative scales and how turbulence influences reconnection (Lapenta 2008;Kowal and Lazarian 2010;El-Alaoui et al 2012. Studies using MMS data will probe further how turbulence changes the reconnection process and can affect the reconnection rate Lamkin 1985, 1986;Goldstein et al 1986;Strauss 1988;Klimas et al 2010;Eyink et al 2011).…”

Section: Reconnection and Turbulencementioning

confidence: 99%

Mission Oriented Support and Theory (MOST) for MMS—the Goddard Space Flight Center/University of California Los Angeles Interdisciplinary Science Program

et al. 2015

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The MOST IDS team was tasked with focusing on two general areas: The first was to participate with the Fast Plasma Investigation (FPI) team in the development of virtual detectors that model the instrument responses of the MMS FPI sensors. The virtual instruments can be "flown through" both simulation data (from magnetohydrodynamic, hybrid, and kinetic simulations) and Cluster and THEMIS spacecraft data. The goal is to determine signatures of magnetic reconnection expected during the MMS mission. Such signatures can serve as triggers for selection of burst mode downloads. The chapter contributed by the FPI team covers that effort in detail and, therefore, most of that work has not been included here. The second area of emphasis, and the one detailed in this chapter, was to build on past and present knowledge of magnetic reconnection and its physical signatures. Below we describe intensive analyses of Cluster and THEMIS data together with theoretical models and simulations that delineate the plasma signatures that surround sites of reconnection, including the effects of turbulence as well as the detailed kinetic signatures that indicate proximity to reconnection sites. In particular, we point out that particles are energized in several regions, not only at the actual site of reconnection.

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Acceleration of charged particles in magnetic reconnection: Solar flares, the magnetosphere, and solar wind

Cited by 46 publications

References 17 publications

Comparison of test particle acceleration in torsional spine and fan reconnection regimes

Comparison of test particle acceleration in torsional spine and fan reconnection regimes

Magnetic moment nonconservation in magnetohydrodynamic turbulence models

Mission Oriented Support and Theory (MOST) for MMS—the Goddard Space Flight Center/University of California Los Angeles Interdisciplinary Science Program

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