Time of flight dispersed and repetitive ion structures in the diffuse auroral zone originating from 1-2 Re altitudes

International audienceThe AMBRE experiment onboard the ocean topography mapper JASON-3 aims at measuring auroral particle precipitation using two top-hat analyzers for electrons and ions in the 20 eV-28 keV energy range. The JASON-3 spacecraft that has a nearly circular orbit at an altitude of 1336 km with an inclination of 66◦ , at times probes the equatorward part of the auroral oval in a nearly tangentially manner upon leaving the outer radiation belt. In this region of space, during periods of enhanced geomagnetic activity with small or moderate storms, AMBRE detected recurrent ion bands/micro-injections with energies in the 200 eV-28 keV range and which exhibit clear time of flight dispersions. Ray tracing using single trajectory computations suggests that these ions are launched from a source located in the 8000-12000 km altitudinal range and subsequently propagate downward toward the ionosphere. More radial orbits show that the ion bands are detected inside the diffuse auroral zone up to the encounter of auroral arcs. Such observations of dispersed downflowing ions are new and we argue that these structures are produced by localized wave-particle interactions

Properties of Interplanetary Fast Shocks Close to the Martian Environment

International audienceMagnetic field and plasma measurements from the Mars Atmosphere and Volatile EvolutioN mission in orbit around Mars are analyzed for interplanetary fast shock properties and drivers from 2014 October to 2018 November. We identified 52 fast shocks, including 39 fast forward (FF) shocks and 13 fast reverse (FR) shocks. Most (79%) of the FF shocks are driven by stream interaction regions (SIRs) with only a few cases being driven by interplanetary coronal mass ejections, and all of the FR shocks are driven by SIRs. A total of 92% of the identified shocks are quasi-perpendicular shocks. On average, the shock strengths of SIR-driven forward and reverse shocks are comparable, and they are greater than that of ICME-driven forward shocks. The shock strengths show no systematic dependence on the shock locations relative to the Martian bow shock. We find no evidence that the shock shapes are affected by Mars and its bow shock as an obstacle in the propagating medium. The results can help us understand the nature of interplanetary shocks propagating in different environments

Electron acceleration observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby

International audienceBepiColombo was launched in October 2018 and is currently en route to Mercury. Although its orbit insertion is planned for December 2025, BepiColombo will acquire new measurements during planetary flybys. During the cruise phase, the two spacecraft are docked together with Mio being protected behind the MOSIF sun shield. Thus, only partial observations of plasma distribution functions can be obtained by the Mercury Plasma Particle Experiment (MPPE) onboard Mio. However, since electrons have small Larmor radii and more isotropic distributions even in the solar wind, the two Mercury Electron Analyzer (MEA) of MPPE will provide us with new and unique measurements in the range of 5 eV to 3 keV when in solar wind mode and 3 eV to ~ 26 keV when in magnetospheric mode. We will present the interesting observations obtained by MEA onboard Mio/BepiColombo during its second Mercury flyby that happened on the 23rd of June, 2022. In particular we will focus on the properties of the low-energy electron populations and inverted-V structures observed during its crossing of Mercury's magnetosphere

Electron acceleration observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby

International audienceBepiColombo was launched in October 2018 and is currently en route to Mercury. Although its orbit insertion is planned for December 2025, BepiColombo will acquire new measurements during planetary flybys. During the cruise phase, the two spacecraft are docked together with Mio being protected behind the MOSIF sun shield. Thus, only partial observations of plasma distribution functions can be obtained by the Mercury Plasma Particle Experiment (MPPE) onboard Mio. However, since electrons have small Larmor radii and more isotropic distributions even in the solar wind, the two Mercury Electron Analyzer (MEA) of MPPE will provide us with new and unique measurements in the range of 5 eV to 3 keV when in solar wind mode and 3 eV to ~ 26 keV when in magnetospheric mode. We will present the interesting observations obtained by MEA onboard Mio/BepiColombo during its second Mercury flyby that happened on the 23rd of June, 2022. In particular we will focus on the properties of the low-energy electron populations and inverted-V structures observed during its crossing of Mercury's magnetosphere

Structure and Variability of Low-Energy Ions in Mercury's Magnetosphere: Initial Results from BepiColombo Mio MIA Observations

International audienceWe present initial results from low-energy ion measurements by the Mercury Ion Analyzer (MIA) on board BepiColombo Mio during the first and second Mercury flybys. The orbital configurations of the two flybys were very similar, but the ion properties observed by MIA are significantly different presumably because of different upstream solar wind conditions. Specifically, the ion energies are generally lower during the first flyby than the second flyby, suggesting slower solar wind conditions in the former case. The ion energy spectra obtained during the first flyby suggest the presence of a relatively cold dense ion component in the midnight magnetotail, sources and transport mechanisms of which remain elusive. Additionally, by utilizing an MIA data product that is originally designed to separate ion directions according to the spacecraft spin phase, we derive bonus data of high-time resolution (>~1 s) ion flux measurements from non-spinning observations during the cruise phase. Such high-time resolution measurements could be useful to investigate boundary dynamics, ion kinetics, etc. These flyby observations with limited capabilities suggest rich dynamics of low-energy ions in Mercury's magnetosphere, more complete views of which will be derived from future in-orbit observations of full 3-dimensional ion velocity distribution functions by MIA, along with ion composition and magnetic field measurements by other instruments on Mio

Electron acceleration observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby

International audienceBepiColombo was launched in October 2018 and is currently en route to Mercury. Although its orbit insertion is planned for December 2025, BepiColombo will acquire new measurements during planetary flybys. During the cruise phase, the two spacecraft are docked together with Mio being protected behind the MOSIF sun shield. Thus, only partial observations of plasma distribution functions can be obtained by the Mercury Plasma Particle Experiment (MPPE) onboard Mio. However, since electrons have small Larmor radii and more isotropic distributions even in the solar wind, the two Mercury Electron Analyzer (MEA) of MPPE will provide us with new and unique measurements in the range of 5 eV to 3 keV when in solar wind mode and 3 eV to ~ 26 keV when in magnetospheric mode. We will present the interesting observations obtained by MEA onboard Mio/BepiColombo during its second Mercury flyby that happened on the 23rd of June, 2022. In particular we will focus on the properties of the low-energy electron populations and inverted-V structures observed during its crossing of Mercury's magnetosphere

BepiColombo Mio Observations of Low‐Energy Ions During the First Mercury Flyby: Initial Results

International audience• We present initial reports on low energy ion observations during BepiColombo's first Mercury flyby • Mio observed large fluctuations of ion flux with time scales down to a few seconds around the magnetopause and within the magnetosphere • Ion energy spectra obtained in the midnight magnetotail suggest the presence of an unexpectedly dense cold componen

Structure and Variability of Low-Energy Ions in Mercury's Magnetosphere: Initial Results from BepiColombo Mio MIA Observations

International audienceWe present initial results from low-energy ion measurements by the Mercury Ion Analyzer (MIA) on board BepiColombo Mio during the first and second Mercury flybys. The orbital configurations of the two flybys were very similar, but the ion properties observed by MIA are significantly different presumably because of different upstream solar wind conditions. Specifically, the ion energies are generally lower during the first flyby than the second flyby, suggesting slower solar wind conditions in the former case. The ion energy spectra obtained during the first flyby suggest the presence of a relatively cold dense ion component in the midnight magnetotail, sources and transport mechanisms of which remain elusive. Additionally, by utilizing an MIA data product that is originally designed to separate ion directions according to the spacecraft spin phase, we derive bonus data of high-time resolution (>~1 s) ion flux measurements from non-spinning observations during the cruise phase. Such high-time resolution measurements could be useful to investigate boundary dynamics, ion kinetics, etc. These flyby observations with limited capabilities suggest rich dynamics of low-energy ions in Mercury's magnetosphere, more complete views of which will be derived from future in-orbit observations of full 3-dimensional ion velocity distribution functions by MIA, along with ion composition and magnetic field measurements by other instruments on Mio

Structure and Variability of Low-Energy Ions in Mercury's Magnetosphere: Initial Results from BepiColombo Mio MIA Observations

International audienceWe present initial results from low-energy ion measurements by the Mercury Ion Analyzer (MIA) on board BepiColombo Mio during the first and second Mercury flybys. The orbital configurations of the two flybys were very similar, but the ion properties observed by MIA are significantly different presumably because of different upstream solar wind conditions. Specifically, the ion energies are generally lower during the first flyby than the second flyby, suggesting slower solar wind conditions in the former case. The ion energy spectra obtained during the first flyby suggest the presence of a relatively cold dense ion component in the midnight magnetotail, sources and transport mechanisms of which remain elusive. Additionally, by utilizing an MIA data product that is originally designed to separate ion directions according to the spacecraft spin phase, we derive bonus data of high-time resolution (>~1 s) ion flux measurements from non-spinning observations during the cruise phase. Such high-time resolution measurements could be useful to investigate boundary dynamics, ion kinetics, etc. These flyby observations with limited capabilities suggest rich dynamics of low-energy ions in Mercury's magnetosphere, more complete views of which will be derived from future in-orbit observations of full 3-dimensional ion velocity distribution functions by MIA, along with ion composition and magnetic field measurements by other instruments on Mio

Forecasting Heliospheric CME Solar-Wind Parameters Using the UCSD Time-Dependent Tomography and ISEE Interplanetary Scintillation Data: The 10 March 2022 CME

International audienceRemotely sensed interplanetary scintillation (IPS) data from the Institute for Space-Earth Environmental Research (ISEE), Japan, allows a determination of solar-wind parameters throughout the inner heliosphere. We show the 3D analysis technique developed for these data sets that forecast plasma velocity, density, and component magnetic fields at Earth, as well at the other inner heliospheric planets and spacecraft. One excellent coronal mass ejection (CME) example that occurred on the 10 March 2022 was viewed not only in the ISEE IPS analyses, but also by the spacecraft near Earth that measured the CME arrival at one AU. Solar Orbiter, that was nearly aligned along the Earth radial at 0.45 AU, also measured the CME in plasma density, velocity, and magnetic field. BepiColombo at 0.42 AU was also aligned with the STEREO A spacecraft, and viewed this CME. The instruments used here from BepiColombo include: 1) the European-Space-Agency Mercury-Planetary-Orbiter magnetic field measurements; 2) the Japan Aerospace Exploration Agency Mio spacecraft Solar Particle Monitor that viewed the CME Forbush decrease, and the Mercury Plasma Experiment/Mercury Electron Analyzer instruments that measured particles and solar-wind density from below the spacecraft protective sunshield covering. This article summarizes the analysis using ISEE, Japan real-time data for these forecasts: it provides a synopsis of the results and confirmation of the CME event morphology after its arrival, and discusses how future IPS analyses can augment these results