Publications

2024

• Global Environmental Constraints on Magnetic Reconnection at the Magnetopause From In Situ Measurements
  
  • Michotte de Welle B.
  • Aunai N.
  • Lavraud B.
  • Génot V.
  • Nguyen G.
  • Ghisalberti A.
  • Smets R.
  • Jeandet A.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2024, 129 (8), pp.e2023JA032098. Progress in locating the X‐line on the magnetopause beyond the atypical due south interplanetary magnetic field (IMF) condition is hampered by the fact that the global plasma and field spatial distributions constraining where reconnection could develop on the magnetopause are poorly known. This work presents global maps of the magnetic shear, current density and reconnection rate, on the global dayside magnetopause, reconstructed from two decades of measurements from Cluster, Double Star, THEMIS and MMS missions. These maps, generated for various IMF and dipole tilt angles, offer a unique comparison point for models and observations. The magnetic shear obtained from vacuum magnetostatic draping is shown to be inconsistent with observed shear maps for IMF cone angles in 12.5° ± 2.5° ≤ | θ co | ≤ 45° ± 5°. Modeled maximum magnetic shear lines fail to incline toward the equator as the IMF clock angle increases, in contrast to those from observations and MHD models. Reconnection rate and current density maps are closer together than they are from the shear maps, but this similarity vanishes for increasingly radial IMF orientations. The X‐lines maximizing the magnetic shear are the only ones to sharply turns toward and follow the anti‐parallel ridge at high latitude. We show the behavior of X‐lines with varying IMF clock and dipole tilt angles to be different as the IMF cone angle varies. Finally, we discuss a fundamental disagreement between X‐lines maximizing a given quantity on the magnetopause and predictions of local X‐line orientations. (10.1029/2023JA032098)
  DOI : 10.1029/2023JA032098
• Magnetospheric Venus Space Explorers (MVSE) mission: A proposal for understanding the dynamics of induced magnetospheres
  
  • Albers Roland
  • Andrews Henrik
  • Boccacci Gabriele
  • Pires Vasco D C
  • Laddha Sunny
  • Lundén Ville
  • Maraqten Nadim
  • Matias João
  • Krämer Eva
  • Schulz Leonard
  • Palanca Ines Terraza
  • Teubenbacher Daniel
  • Baskevitch Claire
  • Covella Francesca
  • Cressa Luca
  • Moreno Juan Garrido
  • Gillmayr Jana
  • Hollowood Joshua
  • Huber Kilian
  • Kutnohorsky Viktoria
  • Lennerstrand Sofia
  • Malatinszky Adel
  • Manzini Davide
  • Maurer Manuel
  • Nidelea Daiana Maria Alessandra
  • Rigon Luca
  • Sinjan Jonas
  • Suarez Crisel
  • Viviano Mirko
  • Knutsen Elise Wright
  Acta Astronautica, Elsevier, 2024, 221, pp.194-205. Induced magnetospheres form around planetary bodies with atmospheres through the interaction of the solar wind with their ionosphere. Induced magnetospheres are highly dependent on the so- lar wind conditions and have only been studied with single spacecraft missions in the past. This gap in knowledge could be addressed by a multi-spacecraft plasma mission, optimized for study- ing global spatial and temporal variations in the magnetospheric system around Venus, which hosts the most prominent example of an induced magnetosphere in our solar system. The MVSE mission comprises four satellites, of which three are identical scientific spacecraft, carrying the same suite of instruments probing different regions of the induced magnetosphere and the solar wind simultaneously. The fourth spacecraft is the transfer vehicle which acts as a relay satellite for communications at Venus. In this way, changes in the solar wind conditions and extreme solar events can be observed, and their effects can be quantified as they propagate through the Venusian induced magnetosphere. Additionally, energy transfer in the Venusian induced mag- netosphere can be investigated. The scientific payload includes instrumentation to measure the magnetic field, electric field, and ion-electron velocity distributions. This study presents the scientific motivation for the mission as well as requirements and the resulting mission design. Concretely, a mission timeline along with a complete spacecraft design, including mass, power, communication, propulsion and thermal budgets are given. This mission was initially conceived at the Alpbach Summer School 2022 and refined during a week-long study at ESA’s Concurrent Design Facility in Redu, Belgium (10.1016/j.actaastro.2024.05.017)
  DOI : 10.1016/j.actaastro.2024.05.017
• Structure and dynamics of the Hermean magnetosphere revealed by electron observations from the Mercury electron analyzer after the first three Mercury flybys of BepiColombo
  
  • Rojo M.
  • André N.
  • Aizawa Sae
  • Sauvaud Jean‐andré
  • Saito Y.
  • Harada Y.
  • Fedorov A.
  • Penou E.
  • Barthe A.
  • Persson M.
  • Yokota S.
  • Mazelle C.
  • Hadid L.
  • Delcourt D.
  • Fontaine D.
  • Fränz M.
  • Katra B.
  • Krupp N.
  • Murakami G.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2024, 687, pp.A243. Context: The Mercury electron analyzer (MEA) obtained new electron observations during the first three Mercury flybys by BepiColombo on October 1, 2021 (MFB1), June 23 , 2022 (MFB2), and June 19, 2023 (MFB3). BepiColombo entered the dusk side magnetotail from the flank magnetosheath in the northern hemisphere, crossed the Mercury solar orbital equator around midnight in the magnetotail, traveled from midnight to dawn in the southern hemisphere near the closest approach, and exited from the post-dawn magnetosphere into the dayside magnetosheath. Aims: We aim to identify the magnetospheric boundaries and describe the structure and dynamics of the electron populations observed in the various regions explored along the flyby trajectories. Methods: We derive 4s time resolution electron densities and temperatures from MEA observations. We compare and contrast our new BepiColombo electron observations with those obtained from the Mariner 10 scanning electron spectrometer (SES) 49 yr ago. Results: A comparison to the averaged magnetospheric boundary crossings of MESSENGER indicates that the magnetosphere of Mercury was compressed during MFB1, close to its average state during MFB2, and highly compressed during MFB3. Our new MEA observations reveal the presence of a wake effect very close behind Mercury when BepiColombo entered the shadow region, a significant dusk-dawn asymmetry in electron fluxes in the nightside magnetosphere, and strongly fluctuating electrons with energies above 100s eV in the dawnside magnetosphere. Magnetospheric electron densities and temperatures are in the range of 10–30 cm −3 and above a few 100s eV in the pre-midnight-sector, and in the range of 1–100 cm −3 and well below 100 eV in the post-midnight sector, respectively. Conclusions: The MEA electron observations of different solar wind properties encountered during the first three Mercury flybys reveal the highly dynamic response and variability of the solar wind-magnetosphere interactions at Mercury. A good match is found between the electron plasma parameters derived by MEA in the various regions of the Hermean environment and similar ones derived in a few cases from other instruments on board BepiColombo. (10.1051/0004-6361/202449450)
  DOI : 10.1051/0004-6361/202449450