Magnetotail energy dissipation during an auroral substorm

Panov, E. V.; Baumjohann, W.; Wolf, R. A.; Nakamura, R.; Angelopoulos, V.; Weygand, J. M.; Kubyshkina, M. V.

doi:10.1038/nphys3879

Cited by 17 publications

(25 citation statements)

References 41 publications

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“…Such ASI and SECS observations suggest that several DFs were formed by a series of sequentially detached BICI heads. In this case the ionospheric response was similar to the response during oscillatory flow braking (Panov et al, 2016), when every subsequent earthward flow was a result of multiple overshoot and rebound of the original fast flow. Two of the above examples of BICI heads showed duskward propagation (Figures 3 and 4), which is the signature of charge neutral current sheet (see Pritchett & Coroniti, 2010, for PIC simulations and Panov, Sergeev, et al, 2012, for comparison with in situ observations).…”

Section: 1029/2019gl083070mentioning

confidence: 65%

Ionospheric Footprints of Detached Magnetotail Interchange Heads

Panov

Baumjohann

Nakamura

et al. 2019

Geophysical Research Letters

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Pritchett and Coroniti (2011, https://doi.org/10.1029/2011GL047527, 2013, https://doi.org/10.1029/2012JA018143) have predicted that the kinetic ballooning/interchange instability (BICI) can provoke reconnection onsets that lead to detached azimuthally thin earthward intrusions (heads) of depleted plasma tubes when βeq⩽ 100. Such detached BICI heads would be seen as localized earthward‐propagating dipolarization fronts. Using Time History of Events and Macroscale Interactions during Substorms observations in the plasma sheet at XGSM≈−11RE and conjugate All‐Sky Imager and magnetometer networks observations on the ground, we show four examples when prominent dipolarization fronts with moderate earthward flows were observed amidst azimuthally drifting interchange heads and concurrently with the ionospheric current intensifications near Time History of Events and Macroscale Interactions during Substorms footprints and auroral bright spots originating from dimmer azimuthal beads/rays. These events support the idea that some of the BICI heads detach from the region with reversed radial gradient of BZ due to local reconnection. The detached BICI heads propagate earthward‐driving ionospheric pseudo‐breakups.

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Section: 1029/2019gl083070mentioning

confidence: 65%

Ionospheric Footprints of Detached Magnetotail Interchange Heads

Panov

Baumjohann

Nakamura

et al. 2019

Geophysical Research Letters

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“…This interpretation-that some of the poleward auroral expansion is due to tailward propagation of the dipolarization-was also presented by Panov et al (2016), who stated, "Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during substorm expansion and recovery phases cause faster poleward then slower equatorward movement of the substorm aurora." GOES-11 was farther west and observed the sustained dipolarization 1 min later at 06:35 UT (only 1-min averaged data were available).…”

Section: 1029/2018ja025588mentioning

confidence: 65%

Utilizing the Heliophysics/Geospace System Observatory to Understand Particle Injections: Their Scale Sizes and Propagation Directions

et al. 2019

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The injection region's formation, scale size, and propagation direction have been debated throughout the years, with new questions arising with increased plasma sheet observations by missions like Cluster and THEMIS. How do temporally and spatially small‐scale injections relate to the larger injections historically observed at geosynchronous orbit? How to account for opposing propagation directions—earthward, tailward, and azimuthal—observed by different studies? To address these questions, we used a combination of multisatellite and ground‐based observations to knit together a cohesive story explaining injection formation, propagation, and differing spatial scales and timescales. We used a case study to put statistics into context. First, fast earthward flows with embedded small‐scale dipolarizing flux bundles transport both magnetic flux and energetic particles earthward, resulting in minutes‐long injection signatures. Next, a large‐scale injection propagates azimuthally and poleward/tailward, observed in situ as enhanced flux and on the ground in the riometer signal. The large‐scale dipolarization propagates in a similar direction and speed as the large‐scale electron injection. We suggest small‐scale injections result from earthward‐propagating, small‐scale dipolarizing flux bundles, which rapidly contribute to the large‐scale dipolarization. We suggest the large‐scale dipolarization is the source of the large‐scale electron injection region, such that as dipolarization expands, so does the injection. The >90‐keV ion flux increased and decreased with the plasma flow, which died at the satellites as global dipolarization engulfed them. We suggest the ion injection region at these energies in the plasma sheet is better organized by the plasma flow.

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“…Its magnetotail is particularly significant because it accumulates the energy of the solar wind/magnetosphere interaction and then releases it in the form of substorms, pseudobreakups, bursty bulk flows, and dipolarization fronts (DFs) (Angelopoulos et al, 2013). Near Earth this may be provided by collisional dissipation in the ionospheric plasma (Panov et al, 2016). At the same time, understanding of magnetotail dipolarizations in observations, theory, and simulations is still strongly hindered by the fundamental problem of the missing kinetic description of dissipation processes in collisionless plasmas.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Dissipation Around a Dipolarization Front

Sitnov

Merkin

Roytershteyn

et al. 2018

Geophysical Research Letters

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Kinetic aspects of energy conversion and dissipation near a dipolarization front (DF) in the magnetotail are considered using fully kinetic 3‐D particle‐in‐cell simulations. The energy conversion is described in terms of the pressure dilatation, as well as the double contraction of deviatoric pressure tensor and traceless strain rate tensor, also known as the Pi‐D parameter in turbulence studies. It is shown that in contrast to the fluid dissipation measure, the Joule heating rate, which cannot distinguish between ion and electron dissipation and reveals deep negative dips at the DF, the Pi‐D parameters, as kinetic analogs of the Joule heating rate, are largely positive and drastically different for ions and electrons. Further analysis of these parameters suggests that ions are heated at and ahead of the DF due to their reflection from the front, while electrons are heated at and behind the DF due to the long‐wavelength lower‐hybrid drift instability.

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Magnetotail energy dissipation during an auroral substorm

Cited by 17 publications

References 41 publications

Ionospheric Footprints of Detached Magnetotail Interchange Heads

Ionospheric Footprints of Detached Magnetotail Interchange Heads

Utilizing the Heliophysics/Geospace System Observatory to Understand Particle Injections: Their Scale Sizes and Propagation Directions

Kinetic Dissipation Around a Dipolarization Front

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