Reconnection flow jets in 3D as a source of structured dipolarization fronts

Pritchett, P. L.

doi:10.1186/s40623-015-0264-5

Cited by 10 publications

(19 citation statements)

References 21 publications

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“…This head propagates toward the Earth then breaks up into smaller structures due to the ballooning/interchange instability acting in the narrow region of increasing B z (at the leading edge of the head) and finally produces localized B z enhancements/depletions (see Pritchett & Coroniti, ). A similar breakup of fronts produced by magnetic reconnection localized in the cross‐tail direction has been observed in (Pritchett, , , ). System spatial scales in the simulation box are normalized to the ion gyroradius, ρ i 0 , calculated using the initial magnitude of the current sheet magnetic field, B 0 , and the initial ion temperature T i .…”

Section: Identification Of Mhs In Dipolarization Front Simulationssupporting

confidence: 81%

“…These observational results support the sub‐ion hole formation due to the dipolarization front ballooning/interchange instability. Such an instability can generate localized depressions of B z field (Pritchett, , and references therein). Comparison of observations and PIC simulation of the front dynamics confirms the formation of such holes behind the front.…”

Section: Discussionmentioning

confidence: 99%

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Statistical Properties of Sub‐Ion Magnetic Holes in the Dipolarized Magnetotail: Formation, Structure, and Dynamics

et al. 2019

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Magnetic energy release during magnetic reconnection in the magnetotail leads to fast plasma flows transporting thermal energy toward the inner magnetosphere or deep tail. The interaction of such flows with the ambient plasmas is controlled by forces at the flow's leading edge, manifested as a sharp enhancement of the south‐north component of magnetic field there, which has been called the dipolarization front. In this study, we examine the kinetic plasma structure of equatorial magnetic field perturbations observed behind dipolarization fronts. Using statistical observations of dipolarization fronts in the near‐Earth magnetotail by Time History of Events and Macroscale Interactions during Substorms mission, we find sub‐ion scale (scale is below ion gyroradius) magnetic field depressions (magnetic holes), mostly around the equatorial plane, drifting dawnward. They are populated by hot, transversely anisotropic electrons, likely heated around the front. Combining spacecraft observations, analytical estimates, and particle‐in‐cell simulations, we suggest that these holes result from the ballooning/interchange instability at the dipolarization front. They may represent the nonlinear stage of magnetic field perturbations associated with front instability, which trap hot electrons behind the front. We also discuss the possible role of these holes in scattering and heating electrons and ions in the dipolarized magnetotail.

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Section: Identification Of Mhs In Dipolarization Front Simulationssupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Statistical Properties of Sub‐Ion Magnetic Holes in the Dipolarized Magnetotail: Formation, Structure, and Dynamics

et al. 2019

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“…To initiate reconnection in the present near‐Earth configuration, we follow the procedure employed by Pritchett [, , ] in which the cross‐tail current is “blocked” in a region of finite width in y . This procedure is very effective at initiating localized reconnection, and it essentially represents the imposition of a very large anomalous resistivity that scatters the particles in this region.…”

Section: Simulation Modelmentioning

confidence: 99%

“…The front acted as a thermalization site for the ion bulk flow and contributed significantly to the dissipation of magnetic energy. Pritchett [, , ] used a procedure in which the cross‐tail current was interrupted in a localized region to produce a self‐consistent generation of a localized reconnection configuration. Jet fronts with initial cross‐tail width <12 d i underwent a marked expansion in the ion drift direction, reaching a total width of 15–20 d i regardless of the initial width.…”

Section: Introductionmentioning

confidence: 99%

The interaction of finite‐width reconnection exhaust jets with a dipolar magnetic field configuration

Pritchett

Runov

2017

JGR Space Physics

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The structure and properties of earthward propagating exhaust jets produced by a magnetic reconnection source region localized in the out‐of‐plane direction are investigated with 3‐D particle‐in‐cell simulations that incorporate a realistic plasma sheet configuration in which a dipole magnetic field region is connected to an asymptotic tail equilibrium with finite Bz. The jet is found to separate initially into two segments of width ∼10–15di each (di is the ion inertia length). The dawnward segment moves ahead of the duskward one and continues to intensify, while the latter is buffeted by the return flows generated by the former and stagnates. The leading front develops the characteristic structure of a sharp Bz increase and density drop on a 1–2di scale. The current associated with this Bz increase is carried mainly by the electrons, and the jet front is the site of a Region 1 sense field‐aligned current system. The ions develop a moderate temperature anisotropy with Ti||>Ti⊥ ahead of the front, while the electron temperature remains isotropic. The ion heating behind the front is quasi‐adiabatic, while the nonthermal electron tail is enhanced out to the limit of the simulation spectrum (∼15Eth). The ion velocity distribution function behind the front exhibits a strong parallel phase space enhancement at speeds ∼0.5VA associated with the earthward flow, while closer to the dipole region there is a drop out in parallel phase space at speeds of ∼1.5–2.5VA. The electron distribution is isotropic with an enhanced central plateau extending out to ∼4VA.

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“…The topics and related papers are: control of magnetospheric conditions by solar wind parameters (Kubyshkina et al 2015;Sergeev et al 2015;Troshichev and Sormakov 2015), modeling of reconnection and instabilities in the tail (Birn et al 2015;Pritchett 2015;Uchino and Machida 2015), relationships between relativistic electrons and pulsations in the inner magnetosphere Hajra et al 2015;Teramoto et al 2016), the effects of substorms on ionospheric irregularities and currents (Berngardt et al 2015;Cherniak and Zakharenkova 2015;Connors and Rostoker 2015), auroral disturbances during substorms Tanaka et al 2015), and ground magnetometer chains (Connors et al 2016). In addition, a review paper by Akasofu (2015) based on his presentation at ICS-12 was published in Progress in Earth and Planetary Science.…”

mentioning

confidence: 99%