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  • Journal article
    Desai RT, Zhang Z, Wu X, Lue Cet al., 2021,

    Photodetachment and Test-particle Simulation Constraints on Negative Ions in Solar System Plasmas

    , The Planetary Science Journal, Vol: 2, Pages: 99-99

    <jats:title>Abstract</jats:title> <jats:p>Negative ions have been detected in abundance in recent years by spacecraft across the solar system. These detections were, however, made by instruments not designed for this purpose and, as such, significant uncertainties remain regarding the prevalence of these unexpected plasma components. In this article, the phenomenon of photodetachment is examined, and experimentally and theoretically derived cross-sections are used to calculate photodetachment rates for a range of atomic and molecular negative ions subjected to the solar photon spectrum. These rates are applied to negative ions outflowing from Europa, Enceladus, Titan, Dione, and Rhea and their trajectories are traced to constrain source production rates and the extent to which negative ions are able to pervade the surrounding space environments. Predictions are also made for further negative ion populations in the outer solar system with Triton used as an illustrative example. This study demonstrates how, at increased heliocentric distances, negative ions can form stable ambient plasma populations and can be exploited by future missions to the outer solar system.</jats:p>
  • Journal article
    Johlander A, Battarbee M, Vaivads A, Turc L, Pfau-Kempf Y, Ganse U, Grandin M, Dubart M, Khotyaintsev YV, Caprioli D, Haggerty C, Schwartz SJ, Giles BL, Palmroth Met al., 2021,

    Ion Acceleration Efficiency at the Earth's Bow Shock: Observations and Simulation Results

    , ASTROPHYSICAL JOURNAL, Vol: 914, ISSN: 0004-637X
  • Journal article
    Weiss Z, Concepcion-Mairey F, Pickering JC, Smid Pet al., 2021,

    Emission spectroscopic study of an analytical glow discharge with plane and hollow cathodes: Titanium and iron in argon discharge

    , SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, Vol: 180, ISSN: 0584-8547
  • Journal article
    Starkey MJ, Fuselier SA, Desai MI, Schwartz SJ, Russell CT, Wei H, Madanian H, Mukherjee J, Wilson LBet al., 2021,

    MMS Observations of Energized He<SUP>+</SUP> Pickup Ions at Quasiperpendicular Shocks

    , ASTROPHYSICAL JOURNAL, Vol: 913, ISSN: 0004-637X
  • Journal article
    Gonzalez CA, Tenerani A, Matteini L, Hellinger P, Velli Met al., 2021,

    Proton Energization by Phase Steepening of Parallel-propagating Alfvenic Fluctuations

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 914, ISSN: 2041-8205
  • Journal article
    Quijia P, Fraternale F, Stawarz JE, Vasconez CL, Perri S, Marino R, Yordanova E, Sorriso-Valvo Let al., 2021,

    Comparing turbulence in a Kelvin-Helmholtz instability region across the terrestrial magnetopause (vol 503, pg 4815, 2021)

    , MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 503, Pages: 4828-4828, ISSN: 0035-8711
  • Journal article
    Trotta D, Valentini F, Burgess D, Servidio Set al., 2021,

    Phase space transport in the interaction between shocks and plasma turbulence

    , PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 118, ISSN: 0027-8424
  • Journal article
    Schwartz SJ, Ergun RE, Harald K, Wilson LB, Chen L-J, Goodrich KA, Turner DL, Gingell I, Madanian H, Gershman DJ, Strangeway RJet al., 2021,

    Evaluating the de Hoffmann-Teller cross-shock potential at real collisionless shocks
  • Journal article
    Kuhn-Régnier A, Voulgarakis A, Nowack P, Forkel M, Prentice IC, Harrison SPet al., 2020,

    Supplementary material to &quot;Quantifying the Importance of Antecedent Fuel-Related VegetationProperties for Burnt Area using Random Forests&quot;

    , Biogeosciences, ISSN: 1726-4170
  • Journal article
    Telloni D, Sorriso-Valvo L, Woodham LD, Panasenco O, Velli M, Carbone F, Zank GP, Bruno R, Perrone D, Nakanotani M, Shi C, D'Amicis R, De Marco R, Jagarlamudi VK, Steinvall K, Marino R, Adhikari L, Zhao L, Liang H, Tenerani A, Laker R, Horbury TS, Bale SD, Pulupa M, Malaspina DM, MacDowall RJ, Goetz K, de Wit TD, Harvey PR, Kasper JC, Korreck KE, Larson D, Case AW, Stevens ML, Whittlesey P, Livi R, Owen CJ, Livi S, Louarn P, Antonucci E, Romoli M, O'Brien H, Evans V, Angelini Vet al., 2021,

    Evolution of solar wind turbulence from 0.1 to 1 au during the first parker solar probe-solar orbiter radial alignment

    , Letters of the Astrophysical Journal, Vol: 912, Pages: 1-8, ISSN: 2041-8205

    The first radial alignment between Parker Solar Probe and Solar Orbiter spacecraft is used to investigate the evolution of solar wind turbulence in the inner heliosphere. Assuming ballistic propagation, two 1.5 hr intervals are tentatively identified as providing measurements of the same plasma parcels traveling from 0.1 to 1 au. Using magnetic field measurements from both spacecraft, the properties of turbulence in the two intervals are assessed. Magnetic spectral density, flatness, and high-order moment scaling laws are calculated. The Hilbert–Huang transform is additionally used to mitigate short sample and poor stationarity effects. Results show that the plasma evolves from a highly Alfvénic, less-developed turbulence state near the Sun, to fully developed and intermittent turbulence at 1 au. These observations provide strong evidence for the radial evolution of solar wind turbulence.
  • Journal article
    Galand M, Feldman PD, Bockelee-Morvan D, Biver N, Cheng Y-C, Rinaldi G, Rubin M, Altwegg K, Deca J, Beth A, Stephenson P, Heritier KL, Henri P, Parker JW, Carr C, Eriksson AI, Burch Jet al., 2021,

    Far-ultraviolet aurora identified at comet 67P/Churyumov-Gerasimenko (vol 4, pg 1084, 2020)

    , NATURE ASTRONOMY, ISSN: 2397-3366
  • Journal article
    Gibbins G, Haigh JD, 2021,

    Comments on "global and regional entropy production by radiation Estimated from satellite observations"

    , Journal of Climate, Vol: 34, Pages: 3721-3728, ISSN: 0894-8755

    A recent paper by Kato and Rose reports a negative correlation between the annual mean entropy production rate of the climate and the absorption of solar radiation in the CERES SYN1deg dataset, using the simplifying assumption that the system is steady in time. It is shown here, however, that when the nonsteady interannual storage of entropy is accounted for, the dataset instead implies a positive correlation; that is, global entropy production rates increase with solar absorption. Furthermore, this increase is consistent with the response demonstrated by an energy balance model and a radiative–convective model. To motivate this updated analysis, a detailed discussion of the conceptual relationship between entropy production, entropy storage, and entropy flows is provided. The storage-corrected estimate for the mean global rate of entropy production in the CERES dataset from all irreversible transfer processes is 81.9 mW m−2 K−1 and from only nonradiative processes is 55.2 mW m−2 K−1 (observations from March 2000 to February 2018).
  • Journal article
    Cheng IK, Achilleos N, Masters A, Lewis GR, Kane M, Guio Pet al., 2021,

    Electron bulk heating at Saturn's magnetopause

    , Journal of Geophysical Research: Space Physics, Vol: 126, ISSN: 2169-9380

    Magnetic reconnection at the magnetopause (MP) energizes ambient plasma via the release of magnetic energy and produces an “open” magnetosphere allowing solar wind particles to directly enter the system. At Saturn, the nature of MP reconnection remains unclear. The current study examines electron bulk heating at MP crossings, in order to probe the relationship between observed and predicted reconnection heating proposed by Phan et al. (2013, https://doi.org/10.1002/grl.50917) under open and closed MP, and how this may pertain to the position of the crossings in the Δβ‐magnetic shear parameter space. The electron heating for 70 MP crossings made by the Cassini spacecraft from April 2005 to July 2007 was found using 1d and 3d moment methods. Minimum variance analysis was used on the magnetic field data to help indicate whether the MP is open or closed. We found better agreement between observed and predicted heating for events suggestive of locally “open” MP. For events suggestive of locally “closed” MP, we observed a cluster of points consistent with no electron heating, but also numerous cases with significant heating. Examining the events in the Δβ‐magnetic shear parameter space, we find 83% of events without evidence of energization were situated in the “reconnection suppressed” regime, whilst between 43% to 68% of events with energization lie in the “reconnection possible” regime depending on the threshold used. The discrepancies could be explained by a combination of spatial and temporal variability which makes it possible to observe heated electrons with different conditions from the putative reconnection site.
  • Journal article
    Lai T-K, Hendricks EA, Yau MK, Menelaou Ket al., 2021,

    Roles of Barotropic Instability across the Moat in Inner Eyewall Decay and Outer Eyewall Intensification: Essential Dynamics

    , JOURNAL OF THE ATMOSPHERIC SCIENCES, Vol: 78, Pages: 1411-1428, ISSN: 0022-4928
  • Journal article
    Ma B, Chen L, Wu D, Bale SDet al., 2021,

    Statistics of Low Frequency Cutoffs for Type III Radio Bursts Observed by Parker Solar Probe during Its Encounters 1-5

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 913, ISSN: 2041-8205
  • Journal article
    Diaz-Aguado MF, Bonnell JW, Bale SD, Wang J, Gruntman Met al., 2021,

    Parker Solar Probe FIELDS Instrument Charging in the Near Sun Environment: Part 2: Comparison of In-Flight Data and Modeling Results

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 126, ISSN: 2169-9380
  • Journal article
    Diaz-Aguado MF, Bonnell JW, Bale SD, Wang J, Gruntman Met al., 2021,

    Parker Solar Probe FIELDS Instrument Charging in the Near Sun Environment: Part 1: Computational Model

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 126, ISSN: 2169-9380
  • Journal article
    Hoilijoki S, Pucci F, Ergun RE, Schwartz SJ, Wilder FD, Eriksson S, Chasapis A, Ahmadi N, Webster JM, Burch JL, Torbert RB, Strangeway RJ, Giles BLet al., 2021,

    Origin of Electron-Scale Magnetic Fluctuations Close to an Electron Diffusion Region

    , JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 126, ISSN: 2169-9380
  • Journal article
    Martinovic MM, Klein KG, Huang J, Chandran BDG, Kasper JC, Lichko E, Bowen T, Chen CHK, Matteini L, Stevens M, Case AW, Bale SDet al., 2021,

    Multiscale Solar Wind Turbulence Properties inside and near Switchbacks Measured by the Parker Solar Probe

    , ASTROPHYSICAL JOURNAL, Vol: 912, ISSN: 0004-637X
  • Journal article
    Pulupa M, Bale SD, Curry SM, Farrell WM, Goodrich KA, Goetz K, Harvey PR, Malaspina DM, Raouafi NEet al., 2021,

    Non-Detection of Lightning During the Second Parker Solar Probe Venus Gravity Assist

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 48, ISSN: 0094-8276
  • Journal article
    Gryspeerdt E, Goren T, Smith T, 2021,

    Observing the timescales of aerosol-cloud interactions in snapshot satellite images

    , Atmospheric Chemistry and Physics, Vol: 21, Pages: 6093-6109, ISSN: 1680-7316

    The response of cloud processes to an aerosol perturbation is one of the largest uncertainties in the anthropogenic forcing of the climate. It occurs at a variety of timescales, from the near-instantaneous Twomey effect to the longer timescales required for cloud adjustments. Understanding the temporal evolution of cloud properties following an aerosol perturbation is necessary to interpret the results of so-called “natural experiments” from a known aerosol source such as a ship or industrial site. This work uses reanalysis wind fields and ship emission information matched to observations of ship tracks to measure the timescales of cloud responses to aerosol in instantaneous (or“snapshot”) images taken by polar-orbiting satellites.As in previous studies, the local meteorological environment is shown to have a strong impact on the occurrence and properties of ship tracks, but there is a strong time dependence in their properties. The largest droplet number concentration (Nd) responses are found within 3 h of emission, while cloud adjustments continue to evolve over periods of 10 h or more. Cloud fraction is increased within the early life of ship tracks, with the formation of ship tracks in otherwise clear skies indicating that around 5 %–10 % of clear-sky cases in this region may be aerosol-limited.The liquid water path (LWP) enhancement and the Nd–LWP sensitivity are also time dependent and strong functions of the background cloud and meteorological state. The near-instant response of the LWP within ship tracks may be evidence of a bias in estimates of the LWP response to aerosol derived from natural experiments. These results highlight the importance of temporal development and the background cloud field for quantifying the aerosol impact on clouds, even in situations where the aerosol perturbation is clear.
  • Journal article
    Heyner, Auster, Fornacon, Carr C, Richter, Mieth, Kolhey, Exner, Motschmann, Baumjohann, Matsuoka, Magnes, Berghofer, Fischer, Plaschke, Nakamura, Narita, Delta, Volwerk, Balogh A, Dougherty M, Horbury T, Langlais, Mandea, Masters A, Oliveira, Sanchez-Cano, Slavin, Vennerstrøm, Vogt, Wicht, Glassmeieret al., 2021,

    The BepiColombo Planetary Magnetometer MPO-MAG: what can we Learn from the Hermean magnetic field?

    , Space Science Reviews, Vol: 217, ISSN: 0038-6308

    The magnetometer instrument MPO-MAG on-board the Mercury Planetary Orbiter (MPO) of the BepiColombo mission en-route to Mercury is introduced, with its instrument design, its calibration and scientific targets. The instrument is comprised of two tri-axial fluxgate magnetometers mounted on a 2.9 m boom and are 0.8 m apart. They monitor the magnetic field with up to 128 Hz in a ±2048 nT range. The MPO will be injected into an initial 480×1500 km polar orbit (2.3 h orbital period). At Mercury, we will map the planetary magnetic field and determine the dynamo generated field and constrain the secular variation. In this paper, we also discuss the effect of the instrument calibration on the ability to improve the knowledge on the internal field. Furthermore, the study of induced magnetic fields and field-aligned currents will help to constrain the interior structure in concert with other geophysical instruments. The orbit is also well-suited to study dynamical phenomena at the Hermean magnetopause and magnetospheric cusps. Together with its sister instrument Mio-MGF on-board the second satellite of the BepiColombo mission, the magnetometers at Mercury will study the reaction of the highly dynamic magnetosphere to changes in the solar wind. In the extreme case, the solar wind might even collapse the entire dayside magnetosphere. During cruise, MPO-MAG will contribute to studies of solar wind turbulence and transient phenomena.
  • Journal article
    Mackie A, Brindley HE, Palmer PI, 2021,

    Contrasting observed atmospheric responses to tropical SST warming patterns

    , Journal of Geophysical Research: Atmospheres, Vol: 126, Pages: 1-12, ISSN: 2169-897X

    Equilibrium climate sensitivity (ECS) is a theoretical concept which describes the change in global mean surface temperature that results from a sustained doubling of atmospheric CO2. Current ECS estimates range from ∼1.8 to 5.6 K, reflecting uncertainties in climate feedbacks. The sensitivity of the lower (1,000–700 hPa) and upper (500–200 hPa) troposphere to changes in spatial patterns of tropical sea surface temperature (SST) have been proposed by recent model studies as key feedbacks controlling climate sensitivity. We examine empirical evidence for these proposed mechanisms using 14 years of satellite data. We examine the response of temperature and humidity profiles, clouds, and top‐of‐the‐atmosphere radiation to relative warming in tropical ocean regions when there is either strong convection or subsidence. We find warmer SSTs in regions of strong subsidence are coincident with a decrease in lower tropospheric stability (−0.9 ± 0.4 KK−1) and low cloud cover (∼−6% K−1). This leads to a warming associated with the weakening in the shortwave cooling effect of clouds (4.2 ± 1.9 Wm−2K−1), broadly consistent with model calculations. In contrast, warmer SSTs in regions of strong convection are coincident with an increase in upper tropospheric humidity (3.2 ± 1.5% K−1). In this scenario, the dominant effect is the enhancement of the warming longwave cloud radiative effect (3.8 ± 3.0 Wm−2K−1) from an increase in high cloud cover (∼7% K−1), though changes in the net (longwave and shortwave) effect are not statistically significant (p < 0.003). Our observational evidence supports the existence of mechanisms linking contrasting atmospheric responses to patterns in SST, mechanisms which have been linked to climate sensitivity.
  • Journal article
    Qu Y, Voulgarakis A, Wang T, Kasoar M, Wells C, Yuan C, Varma S, Mansfield Let al., 2021,

    A study of the effect of aerosols on surface ozone through meteorology feedbacks over China

    , Atmospheric Chemistry and Physics, Vol: 21, Pages: 5705-5718, ISSN: 1680-7316

    Interactions between aerosols and gases in the atmosphere have been the focus of an increasing number of studies in recent years. Here, we focus on aerosol effects on tropospheric ozone that involve meteorological feedbacks induced by aerosol–radiation interactions. Specifically, we study the effects that involve aerosol influences on the transport of gaseous pollutants and on atmospheric moisture, both of which can impact ozone chemistry. For this purpose, we use the UK Earth System Model (UKESM1), with which we performed sensitivity simulations including and excluding the aerosol direct radiative effect (ADE) on atmospheric chemistry, and focused our analysis on an area with a high aerosol presence, namely China. By comparing the simulations, we found that ADE reduced shortwave radiation by 11 % in China and consequently led to lower turbulent kinetic energy, weaker horizontal winds and a shallower boundary layer (with a maximum of 102.28 m reduction in north China). On the one hand, the suppressed boundary layer limited the export and diffusion of pollutants and increased the concentration of CO, SO2, NO, NO2, PM2.5 and PM10 in the aerosol-rich regions. The NO/NO2 ratio generally increased and led to more ozone depletion. On the other hand, the boundary layer top acted as a barrier that trapped moisture at lower altitudes and reduced the moisture at higher altitudes (the specific humidity was reduced by 1.69 % at 1493 m on average in China). Due to reduced water vapour, fewer clouds were formed and more sunlight reached the surface, so the photolytical production of ozone increased. Under the combined effect of the two meteorology feedback methods, the annual average ozone concentration in China declined by 2.01 ppb (6.2 %), which was found to bring the model into closer agreement with surface ozone measurements from different parts of China.
  • Journal article
    Hellinger P, Verdini A, Landi S, Papini E, Franci L, Matteini Let al., 2021,

    Scale dependence and cross-scale transfer of kinetic energy in compressible hydrodynamic turbulence at moderate Reynolds numbers

    , PHYSICAL REVIEW FLUIDS, Vol: 6, ISSN: 2469-990X
  • Journal article
    Del Zanna G, Andretta V, Cargill PJ, Corso AJ, Daw AN, Golub L, Klimchuk JA, Mason HEet al., 2021,

    High resolution soft X-ray spectroscopy and the quest for the hot (5-10 MK) plasma in solar active regions

    , Frontiers in Astronomy and Space Sciences, Vol: 8, Pages: 1-19, ISSN: 2296-987X

    We discuss the diagnostics available to study the 5–10 MK plasma in the solar corona, which is key to understanding the heating in the cores of solar active regions. We present several simulated spectra, and show that excellent diagnostics are available in the soft X-rays, around 100 Å, as six ionization stages of Fe can simultaneously be observed, and electron densities derived, within a narrow spectral region. As this spectral range is almost unexplored, we present an analysis of available and simulated spectra, to compare the hot emission with the cooler component. We adopt recently designed multilayers to present estimates of count rates in the hot lines, with a baseline spectrometer design. Excellent count rates are found, opening up the exciting opportunity to obtain high-resolution spectroscopy of hot plasma.
  • Journal article
    Archer MO, DeWitt J, 2021,

    “Thanks for helping me find my enthusiasm for physics”: the lasting impacts “research in schools” projects can have on students, teachers, and schools

    , Geoscience Communication, Vol: 4, Pages: 169-188, ISSN: 2569-7110

    Using 6 years of evaluation data, we assess the medium- and long-term impacts upon a diverse range of students, teachers, and schools from participating in a programme of protracted university-mentored projects based on cutting-edge space science, astronomy, and particle physics research. After having completed their 6-month-long projects, the 14–18-year-old school students report having substantially increased in confidence relating to relevant scientific topics and methods as well as having developed numerous skills, outcomes which are corroborated by teachers. There is evidence that the projects helped increase students' aspirations towards physics, whereas science aspirations (generally high to begin with) were typically maintained or confirmed through their involvement. Longitudinal evaluation 3 years later has revealed that these projects have been lasting experiences for students which they have benefited from and drawn upon in their subsequent university education. Data on students' destinations suggest that their involvement in research projects has made them more likely to undertake physics and STEM degrees than would otherwise be expected. Cases of co-created novel physics research resulting from Physics Research in School Environments (PRiSE) has also seemed to have a powerful effect, not only on the student co-authors, but also participating students from other schools. Teachers have also been positively affected through participating, with the programme having influenced their own knowledge, skills, and pedagogy, as well as having advantageous effects felt across their wider schools. These impacts suggest that similar “research in schools” initiatives may have a role to play in aiding the increased uptake and diversity of physics and/or STEM in higher education as well as meaningfully enhancing the STEM environment within schools.
  • Journal article
    Archer MO, DeWitt J, Thorley C, Keenan Oet al., 2021,

    Evaluating participants' experience of extended interaction with cutting-edge physics research through the PRiSE “research in schools” programme

    , Geoscience Communication, Vol: 4, Pages: 147-168, ISSN: 2569-7110

    Physics in schools is distinctly different from, and struggles to capture the excitement of, university research-level work. Initiatives where students engage in independent research linked to cutting-edge physics within their school over several months might help mitigate this, potentially facilitating the uptake of science in higher education. However, how such initiatives are best supported remains unclear and understudied. This paper evaluates a provision framework, Physics Research in School Environments (PRiSE), using survey data from participating 14–18-year-old students and their teachers to understand their experience of the programme. The results show that PRiSE appears to provide much more positive experiences than typical university outreach initiatives due to the nature of the opportunities afforded over several months, which schools would not be able to provide without external input. The intensive support offered is deemed necessary, with all elements appearing equally important. Based on additional feedback from independent researchers and engagement professionals, we also suggest the framework could be adopted at other institutions and applied to their own areas of scientific research, something which has already started to occur.
  • Journal article
    Archer MO, 2021,

    Schools of all backgrounds can do physics research – on the accessibility and equity of the Physics Research in School Environments (PRiSE) approach to independent research projects

    , Geoscience Communication, Vol: 4, Pages: 189-208, ISSN: 2569-7110

    Societal biases are a major issue in school students' access to and interaction with science. School engagement programmes in science from universities, like independent research projects, which could try and tackle these problems are, however, often inequitable. We evaluate these concerns applied to one such programme, Physics Research in School Environments (PRiSE), which features projects in space science, astronomy, and particle physics. Comparing the schools involved with PRiSE to those of other similar schemes and UK national statistics, we find that PRiSE has engaged a much more diverse set of schools with significantly more disadvantaged groups than is typical. While drop-off occurs within the protracted programme, we find no evidence of systematic biases present. The majority of schools that complete projects return for multiple years with the programme, with this repeated buy-in from schools again being unpatterned by typical societal inequalities. Therefore, a school's ability to succeed in independent research projects appears independent of background within the PRiSE framework. Qualitative feedback from teachers shows that the diversity and equity of the programme, which they attribute to the level of support offered through PRiSE's framework, is valued, and they have highlighted further ways of making the projects potentially even more accessible. Researcher involvement, uncommon in many other programmes, along with teacher engagement and communication are found to be key elements to success in independent research projects overall.
  • Journal article
    Turner DL, Wilson LB, Goodrich KA, Madanian H, Schwartz SJ, Liu TZ, Johlander A, Caprioli D, Cohen IJ, Gershman D, Hietala H, Westlake JH, Lavraud B, Le Contel O, Burch JLet al., 2021,

    Direct multipoint observations capturing the reformation of a supercritical fast magnetosonic shock

    , The Astrophysical Journal Letters, Vol: 911, Pages: 1-11, ISSN: 2041-8205

    Using multipoint Magnetospheric Multiscale (MMS) observations in an unusual string-of-pearls configuration, we examine in detail observations of the reformation of a fast magnetosonic shock observed on the upstream edge of a foreshock transient structure upstream of Earth's bow shock. The four MMS spacecraft were separated by several hundred kilometers, comparable to suprathermal ion gyroradius scales or several ion inertial lengths. At least half of the shock reformation cycle was observed, with a new shock ramp rising up out of the "foot" region of the original shock ramp. Using the multipoint observations, we convert the observed time-series data into distance along the shock normal in the shock's rest frame. That conversion allows for a unique study of the relative spatial scales of the shock's various features, including the shock's growth rate, and how they evolve during the reformation cycle. Analysis indicates that the growth rate increases during reformation, electron-scale physics play an important role in the shock reformation, and energy conversion processes also undergo the same cyclical periodicity as reformation. Strong, thin electron-kinetic-scale current sheets and large-amplitude electrostatic and electromagnetic waves are reported. Results highlight the critical cross-scale coupling between electron-kinetic- and ion-kinetic-scale processes and details of the nature of nonstationarity, shock-front reformation at collisionless, fast magnetosonic shocks.

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