Multipoint Measurements of the Electron Jet of Symmetric Magnetic Reconnection with a Moderate Guide Field

Wilder, F. D.; Ergun, R. E.; Eriksson, S.; Phan, T. D.; Burch, J. L.; Ahmadi, N.; Goodrich, K.; Newman, D. L.; Trattner, K. J.; Torbert, R. B.; Giles, B. L.; Strangeway, R. J.; Magnes, W.; Lindqvist, Per‐Arne; Khotyaintsev, Y. V.

doi:10.1103/physrevlett.118.265101

Cited by 48 publications

(100 citation statements)

References 34 publications

(40 reference statements)

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“…This is comparable in amplitude to the high guide field EDR event reported by Eriksson et al (), where the E || amplitude was ~16 mV/m. This amplitude is also 3 times larger than the burst E || reported by Wilder et al () for the B g = 0.5 event. While there appears to be a trend of increasing E || with increasing guide field, more events with similar plasma conditions would be needed to determine this conclusively.…”

Section: Event Examplescontrasting

confidence: 48%

The Role of the Parallel Electric Field in Electron‐Scale Dissipation at Reconnecting Currents in the Magnetosheath

et al. 2018

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We report observations from the Magnetospheric Multiscale satellites of reconnecting current sheets in the magnetosheath over a range of out‐of‐plane “guide” magnetic field strengths. The currents exhibit nonideal energy conversion in the electron frame of reference, and the events are within the ion diffusion region within close proximity (a few electron skin depths) to the electron diffusion region. The study focuses on energy conversion on the electron scale only. At low guide field (antiparallel reconnection), electric fields and currents perpendicular to the magnetic field dominate the energy conversion. Additionally, electron distributions exhibit significant nongyrotropy. As the guide field increases, the electric field parallel to the background magnetic field becomes increasingly strong, and the electron nongyrotropy becomes less apparent. We find that even with a guide field less than half the reconnecting field, the parallel electric field and currents dominate the dissipation. This suggests that parallel electric fields are more important to energy conversion in reconnection than previously thought and that at high guide field, the physics governing magnetic reconnection are significantly different from antiparallel reconnection.

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Section: Event Examplescontrasting

confidence: 48%

The Role of the Parallel Electric Field in Electron‐Scale Dissipation at Reconnecting Currents in the Magnetosheath

et al. 2018

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“…The speed of V e⊥L is larger than the hybrid upstream Alfvén speed V A,up ~ 440 km/s, where the hybrid upstream Alfvén speed is the geometric mean of the two upstream Alfvén speeds (Cassak & Shay, ). Super‐Alfvénic electron outflow jets extending to tens of d i downstream of X‐line have been predicted in kinetic simulations and observed in reconnection regions with weak and moderate guide fields (Phan et al, ; Zhou, Deng, et al, ; Wilder et al, ). It is interesting to note that a similar electron jet extended downstream of the reconnection region for this event with a large guide field.…”

Section: Current Sheet and Ion Diffusion Regionmentioning

confidence: 92%

Magnetospheric Multiscale Observations of an Ion Diffusion Region With Large Guide Field at the Magnetopause: Current System, Electron Heating, and Plasma Waves

et al. 2018

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We report Magnetospheric Multiscale (MMS) observations of a reconnecting current sheet in the presence of a weak density asymmetry with large guide field at the dayside magnetopause. An ion diffusion region (IDR) was detected associated with this current sheet. Parallel current dominated over the perpendicular current in the IDR, as found in previous studies of component reconnection. Electrons were preferentially heated parallel to the magnetic field within the IDR. The heating was manifested as a flattop distribution below 400 eV. Two types of electromagnetic electron whistler waves were observed within the regions where electrons were heated. One type of whistler wave was associated with nonlinear structures in E|| with amplitudes up to 20 mV/m. The other type was not associated with any structures in E||. Poynting fluxes of these two types of whistler waves were directed away from the X‐line. We suggest that the nonlinear evolution of the oblique whistler waves gave rise to the solitary structures in E||. There was a perpendicular super‐Alfvénic outflow jet that was carried by magnetized electrons. Intense electrostatic lower hybrid drift waves were localized in the current sheet center and were probably driven by the super‐Alfvénic electron jet, the velocity of which was approximately equal to the diamagnetic drift of demagnetized ions. Our observations suggest that the guide field significantly modified the structures (Hall electromagnetic fields and current system) and wave properties in the IDR.

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“…MRX results are compared one‐to‐one against two recent in situ MMS reconnection observations (Eriksson et al, ; Wilder et al, ) at finite guide fields B g / B up =0.5 and 4. To compare the MMS and MRX observations, we use the following scaling transformations: Magnetic fields are normalized to the upstream magnetic field B up , and length scales are normalized to the ion sound gyroradius

ρ_{s} = \sqrt{T_{e 0} false/ m_{i}} \cdot false(m_{i} false/ e B_{tot} false)

, where

B_{tot} = {false(B_{up}^{2} + B_{g}^{2} false)}^{1 false/ 2}

, and using the electron temperature in the current sheet T e 0 .…”

Section: Comparison With Mms Observationsmentioning

confidence: 99%

Energy Conversion by Parallel Electric Fields During Guide Field Reconnection in Scaled Laboratory and Space Experiments

Fox

Wilder

Eriksson

et al. 2018

Geophysical Research Letters

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We present direct and scaled comparisons between laboratory and in situ space observations of magnetic reconnection with a guide field, comparing results from the Magnetospheric Multiscale Mission and the Magnetic Reconnection eXperiment (MRX). While Magnetospheric Multiscale Mission observations obtain high‐resolution and fully kinetic data, MRX observations fully cover the 2‐D reconnection plane near the current sheet, removing uncertainties in situating the measurements compared to the reconnection region. Through scaling transformations, we show a quantitative agreement in magnetic field and current density profiles, which agree within a factor of 2 from each other. The introduction of the guide field causes the energy conversion J·E in the current sheet to be dominated by J||E|| in both cases. However, parallel electric fields reported by recent spacecraft crossings are significantly (5–10 times) larger than values obtained on MRX, highlighting an important issue for understanding energy conversion by reconnection.

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Multipoint Measurements of the Electron Jet of Symmetric Magnetic Reconnection with a Moderate Guide Field

Cited by 48 publications

References 34 publications

The Role of the Parallel Electric Field in Electron‐Scale Dissipation at Reconnecting Currents in the Magnetosheath

The Role of the Parallel Electric Field in Electron‐Scale Dissipation at Reconnecting Currents in the Magnetosheath

Magnetospheric Multiscale Observations of an Ion Diffusion Region With Large Guide Field at the Magnetopause: Current System, Electron Heating, and Plasma Waves

Energy Conversion by Parallel Electric Fields During Guide Field Reconnection in Scaled Laboratory and Space Experiments

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