Kinetic simulations of plasmoid chain dynamics

Markidis, Stefano; Henri, Pierre; Lapenta, Giovanni; Divin, Andrey; Goldman, M. V.; Newman, D. L.; Laure, Erwin

doi:10.1063/1.4817286

Cited by 41 publications

(42 citation statements)

References 53 publications

(77 reference statements)

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“…This poses a challenge to theoretical simulations of the core field generation because a weak guide field reconnection is expected to generate a weak core field [e.g., Karimabadi et al, 1999;Markidis et al, 2013]. Our findings suggest that the core field generation for weak guide reconnection may be due to the 3-D effects, namely, (1) the quadrupole Hall field may have acted as the seed for the core field generation and the flux ropes is formed off the neutral sheet, and (2) the kinking of the flux ropes.…”

Section: Summary and Discussionmentioning

confidence: 99%

Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency

et al. 2014

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The relationship between the core field and the interplanetary magnetic field (IMF) B y has been addressed by spacecraft observations in the magnetotail, but it is not yet fully clear since observations by Slavin et al. (2003) and Borg et al. (2012) show controversial results. In this study, we examine 13 flux ropes from the Cluster observations to show for the first time that the correlation between the core field B core and the IMF B y depends on the guide field B g . For large guide fields (> 20% of the reconnecting field), we show that the B core is found to correlate with the IMF B y . However, for weak guide fields (< 10% of the reconnecting field) we show that the core fields have either a positive or negative polarity, irrespective of the IMF B y . This result indicates that for weak guide field reconnection the core field generation of the magnetotail flux rope is not governed by the external IMF B y . We can explain the previous controversy in terms of the guide field dependency. We also confirm earlier suggestions that for weak guide field reconnection the flux ropes can have a significant core field whose polarity agrees with the ambient quadrupole Hall field. In addition, the Grad-Shafranov reconstruction results suggest that the axis of the flux rope may have been kinked. Our findings are crucial and can help advance theoretical simulations of the core field generation for weak guide reconnection. Discussions of the possible core field generation for weak guide field will be given in terms of 3-D reconnection.

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Section: Summary and Discussionmentioning

confidence: 99%

Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency

et al. 2014

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“…If a random perturbation is allowed, the reconnection site acquires amuck more intricate topology. 34 The outflow from the reconnection region forms two fronts traveling along the plus and minus x direction. We refer to these fronts as DFs.…”

Section: Overview Of the Simulationmentioning

confidence: 99%

Electromagnetic energy conversion in downstream fronts from three dimensional kinetic reconnection

et al. 2014

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The electromagnetic energy equation is analyzed term by term in a 3D simulation of kinetic reconnection previously reported by Vapirev et al. [J. Geophys. Res.: Space Phys. 118, 1435]. The evolution presents the usual 2D-like topological structures caused by an initial perturbation independent of the third dimension. However, downstream of the reconnection site, where the jetting plasma encounters the yet unperturbed pre-existing plasma, a downstream front is formed and made unstable by the strong density gradient and the unfavorable local acceleration field. The energy exchange between plasma and fields is most intense at the instability, reaching several pW/m 3 , alternating between load (energy going from fields to particles) and generator (energy going from particles to fields) regions. Energy exchange is instead purely that of a load at the reconnection site itself in a region focused around the x-line and elongated along the separatrix surfaces. Poynting fluxes are generated at all energy exchange regions and travel away from the reconnection site transporting an energy signal of the order of about S % 10 À3 W=m 2 . V C 2014 AIP Publishing LLC.

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“…Magnetic islands then become extended filaments, modulated or broken by instabilities in the third dimension or by a lack of coherence of the tearing instability (Jaroschek et al 2004;Zenitani & Hoshino 2008;Daughton et al 2011;Liu et al 2011;Kagan et al 2013;Markidis et al 2013). For this reason we may expect more particle mixing, but current sheet particles may also still be trapped in the strong magnetic structure surrounding the filaments.…”

Section: Open Questionsmentioning

confidence: 99%

The energetics of relativistic magnetic reconnection: ion-electron repartition and particle distribution hardness

Melzani

Walder

Folini

et al. 2014

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Collisionless magnetic reconnection is a prime candidate to account for flare-like or steady emission, outflow launching, or plasma heating, in a variety of high-energy astrophysical objects, including ones with relativistic ion-electron plasmas. But the fate of the initial magnetic energy in a reconnection event remains poorly known. What are the amounts assigned to kinetic energy, the ion and electron distribution, and the hardness of the particle distributions? We explored these questions with 2D particle-in-cell simulations of ion-electron plasmas. We find that 45 to 75% of the total initial magnetic energy ends up in kinetic energy, this fraction increasing with the inflow magnetization. Depending on the guide field strength, ions get from 30% to 60% of the total kinetic energy. Particles can be separated into two populations that mix only weakly: (i) particles initially in the current sheet heated by its initial tearing and subsequent contraction of the islands, and (ii) particles from the background plasma that primarily gain energy via the reconnection electric field when passing near the X-point. Particles of (ii) tend to form a power law with an index p = −dlog n(γ)/dlog γ that depends mostly on the inflow Alfvén speed V A and magnetization σ s of species s. For electrons p = 5 to 1.2 for increasing σ e . The highest particle Lorentz factor for ions or electrons increases roughly linearly with time for all the relativistic simulations. This is faster, and the spectra can be harder, than for collisionless shock acceleration. We discuss applications to microquasar and AGN coronae, to extragalactic jets, and to radio lobes. We point out situations where effects, such as Compton drag or pair creation, are important.

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Kinetic simulations of plasmoid chain dynamics

Cited by 41 publications

References 53 publications

Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency

Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency

Electromagnetic energy conversion in downstream fronts from three dimensional kinetic reconnection

The energetics of relativistic magnetic reconnection: ion-electron repartition and particle distribution hardness

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Kinetic simulations of plasmoid chain dynamics

Cited by 41 publications

References 53 publications

Correlation of core field polarity of magnetotail flux ropes with the IMF By: Reconnection guide field dependency

Correlation of core field polarity of magnetotail flux ropes with the IMF By: Reconnection guide field dependency

Electromagnetic energy conversion in downstream fronts from three dimensional kinetic reconnection

The energetics of relativistic magnetic reconnection: ion-electron repartition and particle distribution hardness

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Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency

Correlation of core field polarity of magnetotail flux ropes with the IMF B_y: Reconnection guide field dependency