Dimensionality, Coordinate System and Reference Frame for Analysis of In-Situ Space Plasma and Field Data

Shi, Quanqi; Tian, Anmin; Bai, Shaochun; Hasegawa, Hiroshi; Degeling, A. W.; Pu, Z. Y.; Dunlop, Malcolm; Guo, Ruilong; Yao, Shutao; Zong, Qiugang; Wei, Yuanhuan; Zhou, Xuzhi; Fu, S. Y.; Liu, Z. Q.

doi:10.1007/s11214-019-0601-2

Cited by 59 publications

(106 citation statements)

References 89 publications

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“…Recent reconnection studies (e.g., Burch et al, ) used the LMN coordinate system to describe the fields and plasma signatures associated with the encounter of a reconnection region or X‐line. There are many ways to determine a suitable LMN coordinate system; most common methods are the minimum variance analysis (MVA; Sonnerup & Cahill, ) and the minimum directional derivative (MDD) techniques (Shi et al, , ). However, not shown here, either the MVA or MDD method is unable to accurately determine a stable LMN coordinate system for this particular X‐line encounter.…”

Section: Fields and Plasma Signatures Of Re‐reconnection X‐linementioning

confidence: 99%

“…(top) Eigenvalues computed from the maximum directional derivative (MDD) method (Shi et al, , ) with blue, green, and red color representing the maximum, intermediate, and minimum magnetic field gradient, respectively. (middle) Corresponding maximum gradient eigenvectors from MDD method in Geocentric Solar Magnetospheric coordinate system.…”

Section: Fields and Plasma Signatures Of Re‐reconnection X‐linementioning

confidence: 99%

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Dissipation of Earthward Propagating Flux Rope Through Re‐reconnection with Geomagnetic Field: An MMS Case Study

Poh

Slavin

et al. 2019

JGR Space Physics

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Three‐dimensional global hybrid simulations and observations have shown that earthward‐moving flux ropes (FRs) can undergo magnetic reconnection (or re‐reconnection) with the near‐Earth dipole field to create dipolarization front (DF)‐like signatures that are immediately preceded by brief intervals of negative BZ. The simultaneous erosion of the southward BZ field at the leading edge of the FR and continuous reconnection of lobe magnetic flux at the X‐line tailward of the FR result in the asymmetric south‐north BZ signature in many earthward‐moving FRs and possibly DFs with negative BZ dips prior to their observation. In this study, we analyzed Magnetospheric MultiScale (MMS) observation of fields and plasma signatures associated with the encounter of an ion diffusion region ahead of an earthward‐moving FR on 3 August 2017. The signatures of this re‐reconnection event were (i) +/− BZ reversal, (ii) −/+ bipolar‐type quadrupolar Hall magnetic fields, (iii) northward super‐Alfvénic electron outflow jet of ~1,000–1,500 km/s, (iv) Hall electric field of ~15 mV/m, (v) intense currents of ~40–100 nA/m2, and (vi) J·E′ ~0.11 nW/m3. Our analysis suggests that the MMS spacecraft encounters the ion and electron diffusion regions but misses the X‐line. Our results are in good agreement with particle‐in‐cell simulations of Lu et al. (2016, https://doi.org/10.1002/2016JA022815). We computed a dimensionless reconnection rate of ~0.09 for this re‐reconnection event and through modeling, estimating that the FR would fully dissipate by −16.58 RE. We demonstrated pertubations in the high‐latitude ionospheric currents at the same time of the dissipation of earthward‐moving FRs using ground‐ and space‐based measurements.

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Section: Fields and Plasma Signatures Of Re‐reconnection X‐linementioning

confidence: 99%

Section: Fields and Plasma Signatures Of Re‐reconnection X‐linementioning

confidence: 99%

Dissipation of Earthward Propagating Flux Rope Through Re‐reconnection with Geomagnetic Field: An MMS Case Study

Poh

Slavin

et al. 2019

JGR Space Physics

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“…The full three-dimensional velocity of the reconnection layer is determined using the spatiotemporal difference method (STD) (Shi et al, 2006(Shi et al, , 2019. STD is applied to the ∼3.5-s interval surrounding the magnetopause crossing, as shown in Figures A1b and A1c.…”

Section: 1029/2020ja027985mentioning

confidence: 99%

Multiscale Coupling During Magnetopause Reconnection: Interface Between the Electron and Ion Diffusion Regions

et al. 2020

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Magnetospheric multiscale (MMS) encountered the primary low-latitude magnetopause reconnection site when the interspacecraft separation exceeded the upstream ion inertial length. Classical signatures of the ion diffusion region (IDR), including a subion-Alfvénic demagnetized ion exhaust, a superion-Alfvénic magnetized electron exhaust, and Hall electromagnetic fields, are identified. The opening angle between the magnetopause and magnetospheric separatrix is 30 • ± 5 •. The exhaust preferentially expands sunward, displacing the magnetosheath. Intense pileup of reconnected magnetic flux occurs between the magnetosheath separatrix and the magnetopause in a narrow channel intermediate between the ion and electron scales. The strength of the pileup (normalized values of 0.3-0.5) is consistent with the large angle at which the magnetopause is inclined relative to the overall reconnection coordinates. MMS-4, which was two ion inertial lengths closer to the X line than the other three spacecraft, observed intense electron-dominated currents and kinetic-to-electromagnetic-field energy conversion within the pileup. MMS-1, MMS-2, and MMS-3 did not observe the intense currents nor the particle-to-field energy conversion but did observe the pileup, indicating that the edge of the generation region was contained within the tetrahedron. Comparisons with particle-in-cell simulations reveal that the electron currents and large inclination angle of the magnetopause are interconnected features of the asymmetric Hall effect. Between the separatrix and the magnetopause, high-density inflowing magnetosheath electrons brake and turn into the outflow direction, imparting energy to the normal magnetic field and generating the pileup. The findings indicate that electron dynamics are likely an important influence on the magnetic field structure within the ion diffusion region. Plain Language Summary The Earth's and Sun's magnetic fields meet and can interconnect at the outermost boundary of the Earth's magnetosphere, the magnetopause. Reconnection of the two magnetic fields requires that the motions of the ions and electrons become decoupled from the motion of the field itself. Owing to their greater inertia, the ions becomes decoupled from the magnetic field within a much larger volume of space compared to the electrons. The demagnetization of ions and electrons during magnetic field reconnection are difficult to study simultaneously with in situ data, as both the larger ion and smaller electron scale sizes need to be simultaneously resolved. In this study, we report an observation of magnetopause reconnection with the magnetospheric multiscale (MMS) mission. MMS has instruments capable of resolving the electron scales, and we analyze an event for which the spacecraft were separated by a large enough distance to resolve the ion scales. We find that the electron dynamics are important for influencing the structure of the magnetic fields in the region where ion motions are decoupled from the field.

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“…The propagation direction indicates the direction of propagation of the plasma sheet flapping; the normal direction indicates the tilt of the flapping plasma sheet relative to the X ‐ Y plane; and the speed in the normal direction indicates how fast the plasma sheet moves in the normal direction. Cluster multipoint measurements can be used to determine these parameters (Paschmann & Daly, 1998; Shi et al, 2019). A timing analysis was performed by considering the point at which B X = 0 (Russell et al, 1983) to calculate the normal direction and corresponding speed for the first, second, and third crossings.…”

Section: Observation and Analysesmentioning

confidence: 99%

Observation of the Large‐Amplitude and Fast‐Damped Plasma Sheet Flapping Triggered by Reconnection‐Induced Ballooning Instability

et al. 2020

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In this study, we reported the large-amplitude and fast-damped flapping of the plasma sheet, which co-occurred with magnetic reconnection. Data from the Double Star TC-1 and Cluster satellites were used to analyze the features of the plasma sheet flapping 1.4 R E earthward of an ongoing magnetic reconnection event. The flapping was rapidly damped, and its amplitude decreased from the magnetohydrodynamics scale to the subion scale in 5 min. The variation in the flapping period (from 224 to 20 s) indicated that the source of the flapping had highly dynamic temporal characteristics. The plasma sheet flapping propagated duskward through a kink-like wave with a velocity of 100 km/s, which was in agreement with the group velocity of the ballooning perturbation. A correlation analysis between the magnetic reconnection and plasma sheet flapping indicated that the magnetic reconnection likely facilitated the occurrence of ballooning instability by altering the state of plasma in the downstream plasma sheet. In this regard, the reconnection-induced ballooning instability could be a potential mechanism to generate the flapping motion of the plasma sheet.

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Dimensionality, Coordinate System and Reference Frame for Analysis of In-Situ Space Plasma and Field Data

Cited by 59 publications

References 89 publications

Dissipation of Earthward Propagating Flux Rope Through Re‐reconnection with Geomagnetic Field: An MMS Case Study

Dissipation of Earthward Propagating Flux Rope Through Re‐reconnection with Geomagnetic Field: An MMS Case Study

Multiscale Coupling During Magnetopause Reconnection: Interface Between the Electron and Ion Diffusion Regions

Observation of the Large‐Amplitude and Fast‐Damped Plasma Sheet Flapping Triggered by Reconnection‐Induced Ballooning Instability

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