Thank You to Our 2023 Peer Reviewers Rajaram, Harihar; Aiyyer, Anantha; Camargo, Suzana ...
Geophysical research letters,
16 May 2024, Letnik:
51, Številka:
9
Journal Article
Recenzirano
Odprti dostop
On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters would like to sincerely thank those who reviewed manuscripts for us in 2023. The hours reading ...and commenting on manuscripts not only improve the manuscripts, but also increase the scientific rigor of future research in the field. With the advent of AGU's data policy, many reviewers have also helped immensely to evaluate the accessibility and availability of data, and many have provided insightful comments that helped to improve the data presentation and quality. We greatly appreciate the assistance of the reviewers in advancing open science, which is a key objective of AGU's data policy. We particularly appreciate the timely reviews in light of the demands imposed by the rapid review process at Geophysical Research Letters. We received 4,512 submissions in 2023 and 5,112 reviewers contributed to their evaluation by providing 8,587 reviews in total. We deeply appreciate their contributions.
Plain Language Summary
Individuals in italics provided three or more reviews for GRL in 2023.
Key Points
The editors thank the 2023 peer‐reviewers
This paper gives an overview of the insights into the magnetic reconnection process obtained by in-situ measurements across current sheets found in planetary magnetospheres and the solar wind. ...Emphasis is placed on results that might be of interest to the study of reconnection in regions where no in-situ observations are available. These results include the role of symmetric versus asymmetric boundary conditions, the identification of the onset conditions, the reconnection rates, and the spatial and temporal scales. Special attention is paid to observations in the so-called diffusion region surrounding the reconnection sites, where ions and eventually also electrons become demagnetized and reconnection is initiated.
Context.
Magnetic reconnection is a fundamental process in astrophysical plasmas that enables the dissipation of magnetic energy at kinetic scales. Detecting this process in situ is therefore key to ...furthering our understanding of energy conversion in space plasmas. However, reconnection jets typically scale from seconds to minutes in situ, and as such, finding them in the decades of data provided by solar wind missions since the beginning of the space era is an onerous task.
Aims.
In this work, we present a new approach for automatically identifying reconnection exhausts in situ in the solar wind. We apply the algorithm to Solar Orbiter data obtained while the spacecraft was positioned at between 0.6 and 0.8 AU and perform a statistical study on the jets we detect.
Methods.
The method for automatic detection is inspired by the visual identification process and strongly relies on the Walén relation. It is enhanced through the use of Bayesian inference and physical considerations to detect reconnection jets with a consistent approach.
Results.
Applying the detection algorithm to one month of Solar Orbiter data near 0.7 AU, we find an occurrence rate of seven jets per day, which is significantly higher than in previous studies performed at 1 AU. We show that they tend to cluster in the solar wind and are less likely to occur in the tenuous solar wind (< 10 cm
−3
near 0.7 AU). We discuss why the source and the degree of Alfvénicity of the solar wind might have an impact on magnetic reconnection occurrence.
Conclusions.
By providing a tool to quickly identify potential magnetic reconnection exhausts in situ, we pave the way for broader statistical studies on magnetic reconnection in diverse plasma environments.
On 2001‐12‐02 Wind crossed the dayside magnetopause (MP) at ∼15 MLT and traversed the adjacent low‐latitude boundary layer (LLBL) over a period of 2 hours. The IMF was steady (northward and dawnward) ...during the MP/LLBL encounter. Reconnection flows were observed in the MP that were directed 130° away from the magnetosheath flow direction. In contrast, the LLBL flow was aligned with the magnetosheath flow. The counterstreaming field‐aligned and anti‐field‐aligned electrons have different energies and their fluxes are unbalanced in the open MP whereas they are precisely balanced throughout most of the LLBL indicative of a closed LLBL. These observations indicate that reconnection occurs at the low‐latitude MP during northward IMF (with a significant By), but low‐latitude reconnection is not responsible for the creation of the LLBL. Instead, reconnection appears to be in the process of eroding a pre‐existing LLBL that was created either by diffusive entry or by non‐simultaneous double‐cusp reconnection.
While double ion populations, with a cold population originating from the solar wind and a hotter one from the magnetosphere, are frequently observed in the low‐latitude boundary layers at the ...Earth's magnetopause, similar double electron populations are observed less often. A preliminary study of magnetopause crossings characteristics was used to determine the typical locations and energy spectra of ion and electron populations near the magnetopause. Then, we set up an automated detection algorithm for identifying regions with concomitant double populations in both ion and electron energy spectra. The statistical study was carried out on 7 years of Time History of Events and Macroscale Interactions during Substorms particle data, to determine the interplanetary magnetic field conditions in the upstream solar wind for these double populations. The results suggest that such concomitant ion and electron double population boundary layers form preferentially in the subsolar region and under northward interplanetary magnetic field but with a significant BY component. We interpret this finding as the result of reconnection of the same magnetosheath field line in both hemispheres with at least one end reconnecting in its hemisphere at lower latitude with a closed magnetospheric field line that already contains a hot electron source.
Key Points
Frequent observation of concomitant double electron and ion population in Earth's boundary layers
Statistical analyses show that double populations in both ions and electrons occur mainly at dayside during northward IMF with a large By
Result of reconnection between a magnetosheath field line and a magnetospheric field lines already containing hot electrons
A layer of nearly stagnant cold dense plasma is observed by THEMIS spacecraft in a closed field region immediately inside the dayside magnetopause near the low‐latitude boundary layer on 3 June 2007. ...Using the OpenGGCM global MHD magnetosphere numerical model, we successfully reproduce this observed cold dense plasma layer in the simulation. The simulation results show that reconnection first occurs poleward of the cusp in the northern hemisphere, creating new open field lines extending southward and forming an open field layer; then subsequently occurs in the other hemisphere, creating new closed field lines that capture the magnetosheath plasma and form the dayside cold dense plasma layer. In this event, the open layer and the skin of the cold dense plasma layer have a southward tangential flow while the inner part of the cold dense plasma layer has a more stagnant and more turbulent flow.
We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event ...observed on October 23, 2003 by the Cluster spacecraft. We find that high‐latitude reconnection occurs tailward of both cusps between the IMF and geomagnetic field. The newly created closed magnetic flux tubes capture magnetosheath plasma, and subsequently sink and shrink into the magnetosphere, while convecting tailward. The plasma that enters near the reconnection site is driven sunward and toward the low latitude region initially; it then drifts to the flanks. The captured plasma is characterized by small flow velocity, and it is moderately heated in the reconnection region. In the present case study we find the cold plasma enters the plasma sheet in the near Earth tail where it is observed by Cluster.
More than 490 elliptical aerobraking and science phasing orbits made by Mars Global Surveyor (MGS) in 1997 and 1998 provide unprecedented coverage of the solar wind in the vicinity of the orbits of ...the martian moons Phobos and Deimos. We have performed a comprehensive survey of magnetic field perturbations in the solar wind to search for possible signatures of solar wind interaction with dust or gas escaping from the moons. A total of 1246 solar wind disturbance events were identified and their distribution was examined relative to Phobos, the Phobos orbit, and the Deimos orbit. We find that the spatial distribution of solar wind perturbations does not increase near or downstream of Phobos, Phobos’ orbit, or Deimos’ orbit, which would have been expected if there is significant outgassing or dust escape from the martian moons. Of the 1246 magnetic field perturbation events found in the MGS data set, 11 events were found within 2000
km of the Phobos orbit, while three events were found within 2000
km of the Deimos orbit. These events were analyzed in detail and found to likely have other causes than outgassing/dust escape from the martian moons. Thus we conclude that the amount of gas/dust escaping the martian moons is not significant enough to induce detectable magnetic field perturbations in the solar wind. In essence we have not found any clear evidence in the MGS magnetic field data for outgassing or dust escape from the martian moons.
On February 23, 2001, during southward and strongly dawnward IMF, Wind traversed the distant magnetotail near XGSM = −90 RE. Wind encountered the mantle in the southern hemisphere and a nearly empty ...lobe in the northern hemisphere. In the current layer (plasma sheet), high‐speed tailward plasma jets with plasma density intermediate between the mantle and the lobe were detected. The speed of these flows were 96–99% of the Alfvén speed measured in the deHoffmann‐Teller frame. We interpret these observations as evidence for asymmetric reconnection involving a rotational discontinuity in the distant tail when the density in the two inflow regions are vastly different. This is in contrast to typical symmetric magnetotail reconnection involving two lobes of equal density where the flow acceleration across the slow shock is usually sub‐Alfvénic and the outflow density is enhanced relative to the inflow density. Hall effects are also observed in this event.
We have surveyed field‐aligned electrons at the lobe/plasma sheet boundary and their association with reconnection in the distant magnetotail where reconnection is quasi‐steady and large scale. ...Asymmetric (in energy) counterstreaming electrons are detected in ∼30% of the boundary crossings when high‐speed flows are present in the plasma sheet. In 98% of the electron beam cases the low‐energy electrons are directed toward and the higher‐energy electrons directed away from the X‐line. The well‐organized (by the signs of Bx and Vx) quadrupolar pattern of the electrons indicates that these electrons are associated with reconnection. The low‐energy electrons could be the outer part of the Hall current loop, similar to previous reports in the near‐Earth region. The mean electron energy in the distant tail is a factor of ten lower than in the near‐Earth tail. Our observations suggest that the Hall effect can be detected even at large distances from the diffusion region.
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