Contribution of ion reflection to the energy budgets of dipolarization fronts

Li, Jia‐Zheng; Zhou, X.‐Z.; Angelopoulos, V.; Liu, Jiang; Pan, Dong‐Xiao; Zong, Qiugang

doi:10.1002/2015gl067300

Cited by 12 publications

(14 citation statements)

References 49 publications

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“…The electron current contributes to two‐thirds of the energy conversion at the DF. This indicates that energy conversion at the DF is dominated by electron current, rather than the ion current suggested in previous studies (e.g., Khotyaintsev et al, ; Li et al, ; Sitnov et al, ).…”

Section: Discussionmentioning

confidence: 55%

Electron Jet Detected by MMS at Dipolarization Front

Liu

Vaivads

et al. 2018

Geophysical Research Letters

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Using MMS high‐resolution measurements, we present the first observation of fast electron jet (Ve ~2,000 km/s) at a dipolarization front (DF) in the magnetotail plasma sheet. This jet, with scale comparable to the DF thickness (~ 0.9 di), is primarily in the tangential plane to the DF current sheet and mainly undergoes the E × B drift motion; it contributes significantly to the current system at the DF, including a localized ring‐current that can modify the DF topology. Associated with this fast jet, we observed a persistent normal electric field, strong lower hybrid drift waves, and strong energy conversion at the DF. Such strong energy conversion is primarily attributed to the electron‐jet‐driven current (E ⋅ je ≈ 2 E ⋅ ji), rather than the ion current suggested in previous studies.

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Section: Discussionmentioning

confidence: 55%

Electron Jet Detected by MMS at Dipolarization Front

Liu

Vaivads

et al. 2018

Geophysical Research Letters

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“…Previous numerical simulation has suggested that the main dissipation in DFs is dominated by ions (Sitnov et al, 2009). Ion reflection and acceleration by DF (Eastwood et al, 2015;Huang et al, 2014;Li et al, 2016;P. Wu & Shay, 2012) and ion resonance acceleration by DF (Artemyev et al, 2012) have been suggested as possible mechanisms of ions dissipation.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…However, few investigations have been focused on quantitative evaluation of the energy conversion and transport in the magnetotail associated with DF. In addition, the partition of energy conversion between ions and electrons is still a controversial issue (Birn & Hesse, 2014; Li et al, 2016; C. M. Liu et al, 2018). Based on satellite observations, statistical studies across a wide range of magnetotail are necessary.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Energy Conversion and Transport in the Terrestrial Magnetotail Due to Dipolarization Fronts

et al. 2020

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Dipolarization front (DF) is an important region involved with energy conversion and flux transport in the planet's magnetotail. Using observation data from the recent Magnetospheric Multiscale (MMS) mission, we have identified and analyzed 215 DF events. Significant magnetic energy conversion and transport are observed at the DFs, which show strong dawn-dusk asymmetry. We find that the transport process dominates the change of local magnetic energy. Nearly 70% of the events show net Poynting flux flowing into the DF region. Such effect is more significant than local magnetic energy dissipation, averagely. When DF approaches the near-Earth region, the net flow-in Poynting flux decreases and magnetic energy dissipation increases. Our results suggest that the downstream magnetic energies of transient magnetic reconnections in the midtail may be transported to the near-Earth region by one DF event after another. These intensive strikes to the magnetosphere in the near-planet region may drive stronger storms, compared with the previous knowledge about DF. Plain Language Summary Dipolarization front (DF), a sharp boundary with a scale of ion inertial length, is frequently observed at the nightside of the terrestrial magnetosphere. It is widely believed that DF plays a key role in magnetic flux transport and energy conversion in the magnetotail. Reliable data from Magnetospheric Multiscale (MMS) give us an opportunity to investigate the magnetic energy conversion and transport associated with DF. We have statistically studied 215 DF events and found that the magnetic dissipation increases when DF moves toward the near-Earth region. It is interesting that the change of local magnetic energy mainly results from the net inflow Poynting flux, which is much larger than the magnetic energy dissipation in the midtail. These results suggest that DF has a long lifetime during the transport in the magnetotail and might produce a more intense impact on the inner magnetosphere and ionosphere.

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“…BBFs are usually observed to be associated with magnetic structures characterized by strong (~10 nT), abrupt (several seconds) enhancements of the northward magnetic field component B z , known as dipolarization fronts (DFs) [ Nakamura et al ., ; Runov et al ., , ; Sergeev et al ., ; Zhang et al ., ; Fu et al ., , ]. DFs are important sites of energy conversion where significant electromagnetic energy is converted into plasma thermal and bulk kinetic energy [ Sitnov et al ., ; Hamrin et al ., ; Angelopoulos et al ., ; Hamrin et al ., ; Li et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of high‐latitude precursor flows ahead of dipolarization fronts

Zhou

Runov

et al. 2017

JGR Space Physics

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Dipolarization fronts (DFs), earthward propagating structures in the magnetotail current sheet characterized by sharp enhancements of northward magnetic field, are capable of converting electromagnetic energy into particle kinetic energy. The ions previously accelerated and reflected at the DFs can contribute to plasma flows ahead of the fronts, which have been identified as DF precursor flows in both the near‐equatorial plasma sheet and far from it, near the plasma sheet boundary. Using observations from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft, we show that the earthward particle and energy flux enhancements ahead of DFs are statistically larger farther away from the neutral sheet (at high latitudes) than in the near‐equatorial region. High‐latitude particle and energy fluxes on the DF dawnside are found to be significantly greater than those on the duskside, which is opposite to the dawn‐dusk asymmetries previously found near the equatorial region. Using forward and backward tracing test‐particle simulations, we then explain and reproduce the observed latitude‐dependent characteristics of DF precursor flows, providing a better understanding of ion dynamics associated with dipolarization fronts.

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Contribution of ion reflection to the energy budgets of dipolarization fronts

Cited by 12 publications

References 49 publications

Electron Jet Detected by MMS at Dipolarization Front

Electron Jet Detected by MMS at Dipolarization Front

Magnetic Energy Conversion and Transport in the Terrestrial Magnetotail Due to Dipolarization Fronts

Characteristics of high‐latitude precursor flows ahead of dipolarization fronts

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