Ion temperature anisotropy across a magnetotail reconnection jet

Hietala, Heli; Drake, J. F.; Phan, T. D.; Eastwood, J. P.; McFadden, J. P.

doi:10.1002/2015gl065168

Cited by 64 publications

(81 citation statements)

References 40 publications

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“…For the ions, similar semicircle or half-ring-type VDFs by the Speiser motions were reported by hybrid simulations, 36,39 PIC simulations, 18,25,66 and satellite observations. 25 In particular, Ref.…”

Section: Discussion and Summarymentioning

confidence: 90%

Pseudo-3D PIC modeling of drift-induced spatial inhomogeneities in planar magnetron plasmas

2016

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Particle dynamics in the electron current layer in collisionless magnetic reconnection is investigated by using a particle-in-cell simulation. The electron motion and velocity distribution functions are studied by tracking self-consistent trajectories. New classes of electron orbits are discovered: figure-eight-shaped regular orbits inside the electron jet, noncrossing regular orbits on the jet flanks, noncrossing Speiser orbits, and nongyrotropic electrons in the downstream of the jet termination region. The properties of a super-Alfv enic outflow jet are attributed to an ensemble of electrons traveling through the Speiser orbits. The noncrossing orbits are mediated by the polarization electric field near the electron current layer. The noncrossing electrons are found to be non-negligible in number density. The impact of these new orbits to electron mixing, spatial distribution of energetic electrons, and observational signatures is presented.

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Section: Discussion and Summarymentioning

confidence: 90%

Pseudo-3D PIC modeling of drift-induced spatial inhomogeneities in planar magnetron plasmas

2016

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“…Drake et al [2009] and Hietala et al [2015] showed with particle in cell simulations and tail observations that ions entering the exhaust region are both accelerated up to the Alfvén speed and heated by the exhaust stream, owing to speiser like orbits and bounce between the Hall electric field barriers. For event 1, the cold ions cross into the exhaust region and do not show significant heating inside the separatrix region.…”

Section: Discussionmentioning

confidence: 98%

Cold ion heating at the dayside magnetopause during magnetic reconnection

Toledo‐Redondo

André

Vaivads

et al. 2016

Geophysical Research Letters

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Cold ions of ionospheric origin are known to be present in the magnetospheric side of the Earth's magnetopause. They can be very abundant, with densities up to 100 cm−3. These cold ions can mass load the magnetosphere, changing global parameters of magnetic reconnection, like the Alfvén speed or the reconnection rate. In addition they introduce a new length scale related to their gyroradius and kinetic effects which must be accounted for. We report in situ observations of cold ion heating in the separatrix owing to time and space fluctuations of the electric field. When this occurs, the cold ions are preheated before crossing the Hall electric field barrier. However, when this mechanism is not present cold ions can be observed well inside the reconnection exhaust. Our observations suggest that the perpendicular cold ion heating is stronger close to the X line owing to waves and electric field gradients linked to the reconnection process.

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“…Phase space mixing of cold inflow population and hot accelerated particles most likely creates non-Maxwellian beam distributions susceptible to various anisotropic instabilities [Le et al, 2014;Hietala et al, 2015]. Very large computational domains are needed to investigate the dynamics of such peculiar exhaust configurations.…”

Section: Discussionmentioning

confidence: 99%

Three‐scale structure of diffusion region in the presence of cold ions

et al. 2016

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Kinetic simulations and spacecraft observations typically display the two‐scale structure of collisionless diffusion region (DR), with electron and ion demagnetization scales governing the spatial extent of the DR. Recent in situ observations of the nightside magnetosphere, as well as investigation of magnetic reconnection events at the Earth's magnetopause, discovered the presence of a population of cold (tens of eV) ions of ionospheric origin. We present two‐dimensional particle‐in‐cell simulations of collisionless magnetic reconnection in multicomponent plasma with ions consisting of hot and cold populations. We show that a new cold ion diffusion region scale is introduced in between that of hot ions and electrons. Demagnetization scale of cold ion population is several times (∼4–8) larger than the initial cold ion gyroradius. Cold ions are accelerated and thermalized during magnetic reconnection and form ion beams moving with velocities close to the Alfvén velocity.

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Ion temperature anisotropy across a magnetotail reconnection jet

Cited by 64 publications

References 40 publications

Pseudo-3D PIC modeling of drift-induced spatial inhomogeneities in planar magnetron plasmas

Pseudo-3D PIC modeling of drift-induced spatial inhomogeneities in planar magnetron plasmas

Cold ion heating at the dayside magnetopause during magnetic reconnection

Three‐scale structure of diffusion region in the presence of cold ions

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