Latest in physics.space-ph

total 2397took 0.14s
Full inversion of solar relativistic electron events measured by the Helios spacecraftFeb 18 2019Up to present, the largest data set of SEP events in the inner heliosphere are the observations by the two Helios spacecraft. We re-visit a sample of 15 solar relativistic electron events measured by the Helios mission with the goal of better characterising ... More
Full inversion of solar relativistic electron events measured by the Helios spacecraftFeb 18 2019Feb 19 2019Up to present, the largest data set of SEP events in the inner heliosphere are the observations by the two Helios spacecraft. We re-visit a sample of 15 solar relativistic electron events measured by the Helios mission with the goal of better characterising ... More
The Efficiency of Coherent Radiation from Relativistic ShocksFeb 17 2019We discuss a mechanism for intense electromagnetic wave emission at an astrophysical relativistic shock in a magnetized collisionless plasma. At the magnetized shock, the particle reflection by a compressed magnetic field of the shock produces a ring-like ... More
Evidence for Electron Landau Damping in Space Plasma TurbulenceFeb 15 2019How turbulent energy is dissipated in weakly collisional space and astrophysical plasmas is a major open question. Here, we present the application of a field-particle correlation technique to directly measure the transfer of energy between the turbulent ... More
The solution of the Generalized Kepler's equationFeb 14 2019In the context of general perturbation theories, the main problem of the artificial satellite analyses the motion of an orbiter around an Earth-like planet, only perturbed by its equatorial bulge or J2 effect. By means of a Lie transform and the Krylov-Bogoliubov-Mitropolsky ... More
Forecasting satellite trajectories by interpolating hybrid orbit propagatorsFeb 14 2019A hybrid orbit propagator based on the analytical integration of the Kepler problem is designed to determine the future position and velocity of any orbiter, usually an artificial satellite or space debris fragment, in two steps: an initial approximation ... More
Solar wind charge exchange in cometary atmospheres. I. Charge-changing and ionization cross sections for He and H particles in H$_2$OFeb 13 2019Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet, mass-loading the solar wind through an effective conversion of fast light solar wind ions into slow heavy cometary ions. To understand ... More
Project Lyra: Catching 1I/'Oumuamua - Mission Opportunities After 2024Feb 13 2019In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/'Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation ... More
Self-similar expansion model of cylindrical flux ropes combined with Alfven wave current systemFeb 13 2019Magnetic flux ropes in space are generally connected to some regions electromagnetically. We consider the whole closed current system of the expanding flux ropes including the electric current associated with them. By combining the theories regarding ... More
Direct observations of a surface eigenmode of the dayside magnetopauseFeb 12 2019The abrupt boundary between a magnetosphere and the surrounding plasma, the magnetopause, has long been known to support surface waves. It was proposed that impulses acting on the boundary might lead to a trapping of these waves on the dayside by the ... More
Solar wind charge exchange in cometary atmospheres III. Results from the Rosetta mission to comet 67P/Churyumov-GerasimenkoFeb 12 2019Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet. The ESA/Rosetta mission to comet 67P/Churyumov-Gerasimenko (67P) provides a unique opportunity to study charge-changing processes in ... More
Two-Line Element Estimation From Space Catalog Using Machine LearningFeb 11 2019Two-line elements are widely used for space operations to predict the orbit with a moderate accuracy for 2-3 days. Local optimization methods, such as the nonlinear least squares method with differential corrections, can estimate a TLE as long as there ... More
Low Cost Radiation Hardened Software and Hardware Implementation for CubeSatsFeb 11 2019CubeSats are small satellites used for scientific experiments because they cost less than full sized satellites. Each CubeSat uses an on-board computer. The on-board computer performs sensor measurements, data processing, and CubeSat control. The challenges ... More
Spectral Analysis of the September 2017 Solar Energetic Particle EventsFeb 11 2019An interval of exceptional solar activity was registered in early September 2017, late in the decay phase of solar cycle 24, involving the complex Active Region 12673 as it rotated across the western hemisphere with respect to Earth. A large number of ... More
Stellar energetic particles in the magnetically turbulent habitable zones of TRAPPIST-1-like planetary systemsFeb 11 2019Planets in close proximity to their parent star, such as those in the habitable zones around M dwarfs, could be subject to particularly high doses of particle radiation. We have carried out test-particle simulations of ~GeV protons to investigate the ... More
The multi-scale nature of the solar windFeb 09 2019The solar wind is a magnetized plasma and as such exhibits collective plasma behavior associated with its characteristic spatial and temporal scales. The characteristic length scales include the size of the heliosphere, the collisional mean free paths ... More
A Comparative Study of 2017 July and 2012 July Complex Eruptions: Are Solar Superstorms "Perfect Storms" in Nature?Feb 09 2019It is paramount from both scientific and societal perspectives to understand the generation of extreme space weather. We discuss the formation of solar superstorms based on a comparative study of the 2012 July 23 and 2017 July 23 eruptions. The first ... More
Contextual Predictions for Parker Solar Probe II: Turbulence Properties and Taylor HypothesisFeb 09 2019The Parker Solar Probe (PSP) primary mission extends seven years and consists of 24 orbits of the Sun with descending perihelia culminating in a closest approach of ($\sim 9.8~R_\odot$). In the course of these orbits PSP will pass through widely varying ... More
Predictions for the First Parker Solar Probe EncounterFeb 08 2019We examine Alfv\'en Wave Solar atmosphere Model (AWSoM) predictions of the first Parker Solar Probe (PSP) encounter. We focus on the 12-day closest approach centered on the 1st perihelion. AWSoM (van der Holst et al., 2014) allows us to interpret the ... More
A new HLLD Riemann solver with Boris correction for reducing Alfvén speedFeb 07 2019A new Riemann solver is presented for the ideal magnetohydrodynamics (MHD) equations with the so-called Boris correction. The Boris correction is applied to reduce wave speeds, avoiding an extremely small timestep in MHD simulations. The proposed Riemann ... More
Solar energetic particle propagation in wave turbulence and the possibility of wave generationFeb 06 2019A complete theory for the complex interaction between solar energetic particles and the turbulent interplanetary magnetic field remains elusive. In this work we aim to contribute towards such a theory by modelling the propagation of solar energetic particle ... More
The nature of Elsässer variables in compressible MHDFeb 05 2019The Els\"{a}sser variables are often used in studies of plasma turbulence, in helping differentiate between MHD waves propagating parallel or anti-parallel to the main magnetic field. While for pure Alfv\'en waves in a homogeneous plasma the method is ... More
Physical mechanism of reconnection onset in space plasmasFeb 05 2019Magnetic reconnection plays a crucial role in large dissipative events in space plasmas, such as solar flares and geomagnetic substorms, but there has been much confusion regarding reconnection onset responsible for the explosive events. The main theme ... More
Electron energy partition across interplanetary shocks: I. Methodology and Data ProductFeb 04 2019Analysis of 15314 electron velocity distribution functions (VDFs) within $\pm$2 hours of 52 interplanetary (IP) shocks observed by the \emph{Wind} spacecraft near 1 AU are introduced. The electron VDFs are fit to the sum of three model functions for the ... More
On the statistics of acceleration and loss of relativistic electrons in the outer radiation belt: a superposed epoch analysisFeb 03 2019We investigate the response of the outer Van Allen belt electrons to various types of solar wind and magnetospheric disturbances. We use electron phase space density (PSD) calculations as well as concurrent Pc5 and chorus wave activity observations in ... More
Highly relativistic electron flux enhancement during the weak geomagnetic storm of April-May 2017Feb 03 2019We report observations of energetic electron flux and Phase Space Density (PSD) to show that a relatively weak magnetic storm with $Sym-H_{min} \approx -50 $nT, resulted in a relativistic and ultra--relativistic electron enhancement of two orders of magnitude ... More
Ready functions for calculating the Martian radiation environmentFeb 01 2019Feb 05 2019It is extremely important to understand and model the Martian radiation environment in preparation for future human missions to Mars, especially during extreme and elevated conditions such as an intense solar energetic particle (SEP) event. Such events ... More
Turbulence-driven ion beams in the magnetospheric Kelvin-Helmholtz instabilityJan 31 2019The description of the local turbulent energy transfer, and the high-resolution ion distributions measured by the Magnetospheric Multiscale mission, together provide a formidable tool to explore the cross-scale connection between the fluid-scale energy ... More
The Interplay of the Solar Wind Core and Suprathermal Electrons: A Quasilinear Approach for Firehose InstabilityJan 31 2019In the solar wind an equipartition of kinetic energy densities can be easily established between thermal and suprathermal electrons and the instability conditions are markedly altered by the interplay of these two populations. The new thresholds derived ... More
Hybrid-Kinetic Simulations of Ion Heating in Alfvénic TurbulenceJan 30 2019We present three-dimensional, hybrid-kinetic numerical simulations of driven Alfv\'{e}n-wave turbulence of relevance to the collisionless near-Earth solar wind. Special attention is paid to the spectral transition that occurs near the ion-Larmor scale ... More
3D Magnetic Reconnection with a spatially confined X-line extent -- Implications for Dipolarizing Flux Bundles and the Dawn-Dusk AsymmetryJan 29 2019Using 3D particle-in-cell (PIC) simulations, we study magnetic reconnection with the x-line being spatially confined in the current direction. We include thick current layers to prevent reconnection at two ends of a thin current sheet that has a thickness ... More
Role of reconnection in inertial kinetic-Alfven turbulenceJan 29 2019In a weakly collisional, low-electron-beta plasma, large-scale Alfv\'en turbulence transforms into inertial kinetic-Alfv\'en turbulence at scales smaller than the ion microscale (gyroscale or inertial scale). We propose that at such kinetic scales, the ... More
Generic magnetic field intensity profiles of interplanetary coronal mass ejections at Mercury, Venus and Earth from superposed epoch analysesJan 28 2019We study interplanetary coronal mass ejections (ICMEs) measured by probes at different heliocentric distances (0.3-1AU) to investigate the propagation of ICMEs in the inner heliosphere and determine how the generic features of ICMEs change with heliospheric ... More
Particle-in-Cell Simulations of Plasma Dynamics in Cometary EnvironmentJan 28 2019We perform and analyze global Particle-in-Cell (PIC) simulations of the interaction between solar wind and an outgassing comet with the goal of studying the plasma kinetic dynamics of a cometary environment. To achieve this, we design and implement a ... More
Modelling three-dimensional transport of solar energetic protons in a corotating interaction region generated with EUHFORIAJan 28 2019We introduce a new solar energetic particle (SEP) transport code that aims at studying the effects of different solar wind configurations on SEP events. We focus on the influence of varying solar wind velocities on the energy changes of SEPs, and study ... More
Topological structures of velocity and electric field in the vicinity of a cusp-type magnetic null pointJan 28 2019Topological characteristics reveal important physical properties of plasma structures and astrophysical processes. Physical parameters and constraints are linked with topological invariants, which are important for describing magnetic reconnection scenarios. ... More
Transition from ion-coupled to electron-only reconnection: Basic physics and implications for plasma turbulenceJan 28 2019Using kinetic particle-in-cell (PIC) simulations, we simulate reconnection conditions appropriate for the magnetosheath and solar wind, i.e., plasma beta (ratio of gas pressure to magnetic pressure) greater than 1 and low magnetic shear (strong guide ... More
End to End Satellite Servicing and Space Debris ManagementJan 25 2019There is growing demand for satellite swarms and constellations for global positioning, remote sensing and relay communication in higher LEO orbits. This will result in many obsolete, damaged and abandoned satellites that will remain on-orbit beyond 25 ... More
Determining the Dominant Acceleration Mechanism during Relativistic Magnetic Reconnection in Large-scale SystemsJan 24 2019While a growing body of research indicates that relativistic magnetic reconnection is a prodigious source of particle acceleration in high-energy astrophysical systems, the dominant acceleration mechanism remains controversial. Using a combination of ... More
Discovery of an Electron Gyroradius Scale Current Layer Its Relevance to Magnetic Fusion Energy, Earth Magnetosphere and SunspotsJan 23 2019In the Earth magnetosphere, sunspots and magnetic cusp fusion devices, the boundary between the plasma and the magnetic field is marked by a diamagnetic current layer with a rapid change in plasma pressure and magnetic field strength. First principles ... More
On the rapid forced reconnection in the Sun's corona for its localized heatingJan 23 2019The million-degree hot solar corona maintains its high temperature and compensates for its radiative losses by continuously acquiring an energy flux of $\approx$10$^{3}$ W m$^{-2,}$. Recent studies suggest that energy transport in the solar corona is ... More
Solar wind charge exchange in cometary atmospheres. II. Analytical modelJan 23 2019Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet because they mass-load the solar wind through an effective conversion of fast, light solar wind ions into slow, heavy cometary ions. ... More
Comments on "Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation" by Blanco-Cano et al. (2018)Jan 22 2019Blanco-Cano et al. (2018) intended to find a type of transient event in the solar wind before the terrestrial bow shock using a special type of simulation. However, the simulation results cannot reproduce the main features of the event. Not only are the ... More
Cosmic Noise Absorption During Solar Proton Events in WACCM-D and Riometer ObservationsJan 21 2019Solar proton events (SPEs) cause large-scale ionization in the middle atmosphere leading to ozone loss and changes in the energy budget of the middle atmosphere. The accurate implementation of SPEs and other particle ionization sources in climate models ... More
Concerning pressure and entropy of shock-accelerated heliosheath electronsJan 16 2019We study the behaviour of shocked wind-electrons leaving wind-driving stars after undergoing the outer wind termination shock. As an example, we describe the evolution of the keV-energetic electron distribution function downstream of the heliospheric ... More
The Source Regions of WhistlersJan 15 2019Jan 31 2019We present a new method for identifying the source regions of lightning generated whistlers observed at a fixed location. In addition to the spatial distribution of causative lightning discharges, we calculate the transmission ratio of lightning discharges ... More
Penetrating particle ANalyzer (PAN)Jan 14 2019Jan 21 2019PAN is a scientific instrument suitable for deep space and interplanetary missions. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles ($> \sim$100 MeV/nucleon) in deep space, over at least one full ... More
Attitude Control of Spacecraft Swarms for Visual Mapping of Planetary BodiesJan 13 2019Planetary bodies such as asteroids, comets, and planetary moons are high-value science targets as they hold important information about the formation and evolution of our solar system. However, due to their low-gravity, variable sizes and shapes, dedicated ... More
Magnetospheric Multiscale Observation of Kinetic Signatures in the Alfvén VortexJan 12 2019Alfv\'en vortex is a multi-scale nonlinear structure which contributes to intermittency of turbulence. Despite previous explorations mostly on the spatial properties of the Alfv\'en vortex (i.e., scale, orientation, and motion), the plasma characteristics ... More
First-principles demonstration of diffusive particle acceleration in kinetic simulations of relativistic plasma turbulenceJan 11 2019Nonthermal relativistic plasmas are ubiquitous in astrophysical systems like pulsar wind nebulae and active galactic nuclei, as inferred from their emission spectra. The underlying nonthermal particle acceleration (NTPA) processes have traditionally been ... More
Elpasolite Planetary Ice and Composition Spectrometer (EPICS): A Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary ScienceJan 09 2019Neutron and gamma-ray spectroscopy (NGRS) is a well established technique for studying the geochemical composition and volatile abundance relevant to planetary structure and evolution of planetary bodies. Previous NGRS instruments have used separate gamma-ray ... More
Multi-Revolution Low-Thrust Trajectory Optimization Using Symplectic MethodsJan 09 2019Optimization of low-thrust trajectories that involve a larger number of orbit revolutions is considered a challenging problem. This paper describes a high-precision symplectic method and optimization techniques to solve the minimum-energy low-thrust multi-revolution ... More
Dissipation scale lengths of density turbulence in the inner solar windJan 08 2019Knowing the lengthscales at which turbulent fluctuations dissipate is key to understanding the nature of weakly compressible magnetohydrodynamic turbulence. We use radio wavelength interferometric imaging observations which measure the extent to which ... More
Implementation and validation of the GEANT4/AtRIS code to model the radiation environment at MarsJan 07 2019A new GEANT4 particle transport model -- the Atmospheric Radiation Interaction Simulator (AtRIS, Banjac et al. 2018a. J. Geophys. Res.) -- has been recently developed in order to model the interaction of radiation with planets. The upcoming instrumentational ... More
Observations of Magnetic Reconnection in the Transition Region of Quasi-Parallel ShocksJan 04 2019Using observations of Earth's bow shock by the Magnetospheric Multiscale mission, we show for the first time that active magnetic reconnection is occurring at current sheets embedded within the quasi-parallel shock's transition layer. We observe an electron ... More
Simulations of radiation damage in spacecraft camera for ESA JUICE missionJan 01 2019The JUpiter ICy moons Explorer (JUICE) is an ESA interplanetary spacecraft being developed to perform detailed investigations of the Jupiter system and three of its icy moons: Europa, Callisto and Ganymede. The emphasis will be given on Ganymede as a ... More
Snakes on a Spaceship - An Overview of Python in HeliophysicsJan 01 2019Computational analysis has become ubiquitous within the heliophysics community. However, community standards for peer-review of codes and analysis have lagged behind these developments. This absence has contributed to the reproducibility crisis, where ... More
Evaluation of Kinetic Ballooning Instability in the Near-Earth MagnetotailDec 30 2018Ballooning instabilities are widely believed to be a possible triggering mechanism for the onset of substorm and current disruption initiation in the near-Earth magnetotail. Yet the stability of the kinetic ballooning mode (KBM) in a global and realistic ... More
On the Possibility of Generating Harmonics of the Electron Plasma Frequency in the Solar Atmosphere due to Explosive Instability in a System of Interpenetrating Electron and Ion FlowsDec 29 2018An alternative mechanism is proposed for the generation of harmonics of the electron plasma frequency due to the development of explosive instability in a system of interpenetrating electron and proton flows in the solar atmosphere. The efficiency of ... More
Evaluation of Mother-Daughter Architectures for Asteroid Belt ExplorationDec 28 2018This paper examines the effectiveness of an asteroid exploration architecture comprised of multiple nanosatellite sized spacecraft deployed from a single mother ship into a heliocentric orbit in the main asteroid belt where the mothership is ideally located ... More
A search for signatures of Europa's atmosphere and plumes in Galileo charged particle dataDec 28 2018Remote sensing observations indicate that Europa is surrounded by a tenuous atmosphere. Furthermore, recent observations and historic data from Galileo hint at the occurrence of water vapour eruptions originating from the interior that create 200 km high ... More
Ecology of Near-Earth SpaceDec 25 2018The technical achievements of our civilization are accompanied by certain negative consequences affect the near-Earth space. The problem of clogging of near-Earth space by "space debris" as purely theoretical arose essentially as soon as the first artificial ... More
Observational evidence of magnetic reconnection in the terrestrial bow shock transition regionDec 21 2018We report evidence of magnetic reconnection in the transition region of the terrestrial bow shock when the angle between the shock normal and the immediate upstream magnetic field is 65 degrees. An ion-skin-depth-scale current sheet exhibits the Hall ... More
Global diagnostics of ionospheric absorption during X-ray solar flares based on 8-20MHz noise measured by over-the-horizon radarsDec 20 2018An analysis of noise attenuation during eighty solar flares between 2013 and 2017 was carried out at frequencies 8-20 MHz using thirty-four SuperDARN radars and the EKB ISTP SB RAS radar. The attenuation was determined on the basis of noise measurements ... More
On the 1/f spectrum in the solar wind and its connection with magnetic compressibilityDec 13 2018We discuss properties of Alfv\'enic fluctuations with large amplitude in plasmas characterised by low magnetic field compression. We note that in such systems power laws can not develop with arbitrarily steep slopes at large scales, i.e. when $|\delta ... More
Forecasting Periods of Strong Southward Magnetic Field Following Interplanetary ShocksDec 13 2018Long periods of strong southward magnetic fields are known to be the primary cause of intense geomagnetic storms. The majority of such events are caused by the passage over Earth of a magnetic ejecta. Irrespective of the interplanetary cause, fast-forward ... More
On the generation mechanism of electromagnetic cyclotron waves in the solar wind: statistical results from Wind observationsDec 13 2018Electromagnetic cyclotron waves (ECWs) near the proton cyclotron frequency are frequently observed in the solar wind, yet their generation mechanism is still an open question. Based on the Wind data during the years 2005$-$2015, this paper carries out ... More
Quasilinear Consequences of Turbulent Ion Heating by Magnetic Moment BreakingDec 12 2018The fast solar wind emerging from coronal holes is likely heated and accelerated by the dissipation of magnetohydrodynamic turbulence, but the specific kinetic mechanism resulting in the perpendicular ion heating required by observations is not understood. ... More
On slow solar wind with high Alfvénicity: from composition and microphysics to spectral propertiesDec 05 2018Alfv\'enic fluctuations are very common features in the solar wind and are found especially within the main portion of fast wind streams while the slow wind usually is less Alfv\'enic and more variable. In general, fast and slow wind show many differences ... More
VOEvent for Solar and Planetary SciencesNov 30 2018With its Planetary Space Weather Service (PSWS), the Europlanet-H2020 Research Insfrastructure (EPN2020RI) project is proposing a compelling set of databases and tools to that provides Space Weather forecasting throughout the Solar System. We present ... More
Magneto-immutable turbulence in weakly collisional plasmasNov 29 2018Jan 15 2019We propose that pressure anisotropy causes weakly collisional turbulent plasmas to self-organize so as to resist changes in magnetic-field strength. We term this effect "magneto-immutability" by analogy with incompressibility (resistance to changes in ... More
Supertransient Magnetohydrodynamic Turbulence in Keplerian Shear Flows: The role of the Hall EffectNov 29 2018Space and astrophysical plasmas are frequently found in the regime of differential rotation, where the presence of a magnetic field can result in the magnetorotational instability, directly responsible for important phenomena such as turbulent angular ... More
NIEL DOSE and DLTS Analyses on Triple and Single Junction solar cells irradiated with electrons and protonsNov 27 2018Space solar cell radiation hardness is of fundamental importance in view of the future missions towards harsh radiation environment (like the Jupiter missions) and for the new spacecraft using Electrical Propulsion. In this paper we report the radiation ... More
Geometry, Kinematics and Heliospheric Impact of a Large CME-driven Shock in 2017 SeptemberNov 26 2018A powerful coronal mass ejection (CME) occurred on 2017 September 10 near the end of the declining phase of the historically weak solar cycle 24. We obtain new insights concerning the geometry and kinematics of CME-driven shocks in relation to their heliospheric ... More
On the ion-inertial range density power spectra in solar wind turbulenceNov 25 2018De-magnetised ions in the ion inertial range of quasi-neutral plasmas respond to Kolmogorov inertial range velocity turbulence power spectra via the spectrum of its related induction electric field. Maintenance of electrical quasi-neutrality causes deformation ... More
Stochastic proton heating by kinetic-Alfvén-wave turbulence in moderately high-$β$ plasmasNov 21 2018Stochastic heating refers to an increase in the average magnetic moment of charged particles interacting with electromagnetic fluctuations whose frequencies are smaller than the particles' cyclotron frequencies. This type of heating arises when the amplitude ... More
Photometric Study of the C/2014 Q2 (Lovejoy) Comet Plasma TailsNov 16 2018Observations of C/2014 Q2 (Lovejoy) comet were carried out on 7th February, 2015, at the observation station in Mayaki village (No. 583 -- Odesa-Mayaki observatory). The integrated-light photometry of the comet was conducted using RC-800 telescope (D ... More
The potential of IORIO as relativity probe; the impact of the mismodeling in the Jovian gravity field multipolesOct 31 2018The IORIO (In-Orbit Relativity Iuppiter Observatory) concept consists of a fast orbiter of Jupiter $\left(P_\textrm{b}\simeq 0.12~\textrm{d}\right)$, endowed with a Juno-type Doppler ranging device, accurate to $\sigma_{\dot\rho}\simeq 0.003~\textrm{mm~s}^{-1}$, ... More
Inertial Kinetic-Alfvén TurbulenceOct 29 2018Recent observational and analytical studies suggested that a new regime of kinetic turbulence may exist in plasma environments with low electron beta (Chen and Boldyrev, 2017). Such a regime, termed inertial kinetic-Alfv\'en turbulence, is relevant for ... More
Optical communication on CubeSats - Enabling the next era in space scienceOct 26 2018CubeSats are excellent platforms to rapidly perform simple space experiments. Several hundreds of CubeSats have already been successfully launched in the past few years and the number of announced launches grows every year. These platforms provide an ... More
Seasonal, Solar Zenith Angle, and Solar Flux Variations of O$^+$ in the Topside Ionosphere of MarsOct 18 2018Using observations from MAVEN's Neutral Gas and Ion Mass Spectrometer (NGIMS), we characterize the seasonal, solar zenith angle (SZA), and solar flux variations of the O$^+$ peak and the O$^+$/O$_2^+$ ratio in the topside ionosphere of Mars. We find that ... More
Forecasting the Arrival Time of Coronal Mass Ejections: Analysis of the CCMC CME ScoreboardOct 16 2018Accurate forecasting of the properties of coronal mass ejections as they approach Earth is now recognized as an important strategic objective for both NOAA and NASA. The time of arrival of such events is a key parameter, one that had been anticipated ... More
Onset of magnetic reconnection in a collisionless, high-beta plasmaOct 09 2018Jan 06 2019In a magnetized, collisionless plasma, the magnetic moment of the constituent particles is an adiabatic invariant. An increase in the magnetic-field strength in such a plasma thus leads to an increase in the thermal pressure perpendicular to the field ... More
A general relativistic gravitomagnetic effect on the orbital motion of a test particle around its primary induced by the spin of a distant third bodySep 30 2018We study a general relativistic gravitomagnetic 3rd-body effect induced by the spin angular momentum ${\boldsymbol{S}}_\textrm{X}$ of a rotating mass $M_\textrm{X}$ orbited at distance $r_\textrm{X}$ by a local gravitationally bound restricted two-body ... More
The Fluxgate-Searchcoil Merged (FSM) Magnetic Field Data Product for MMSSep 19 2018The Fluxgate-Searchcoil Merged (FSM) data product for the Magnetospheric Multiscale (MMS) mission is created by combining the level-2 science quality data from the fluxgate and searchcoil magnetometers into a single level-3 data product. The merging method ... More
Electron-Scale Dynamics of the Diffusion Region during Symmetric Magnetic Reconnection in SpaceSep 18 2018Magnetic reconnection is an energy conversion process important in many astrophysical contexts including the Earth's magnetosphere, where the process can be investigated in-situ. Here we present the first encounter of a reconnection site by NASA's Magnetospheric ... More
On testing frame-dragging with LAGEOS and a recently announced geodetic satelliteSep 18 2018Oct 22 2018Recently, Ciufolini and coworkers announced the forthcoming launch of a new cannonball geodetic satellite in 2019. It should be injected in an essentially circular path with the same semimajor axis $a$ of LAGEOS, in orbit since 1976, and an inclination ... More
Measuring general relativistic dragging effects in the Earth's gravitational field with ELXIS: a proposalSep 17 2018Jan 10 2019In a geocentric kinematically rotating ecliptical coordinate system in geodesic motion through the deformed spacetime of the Sun, both the longitude of the ascending node $\Omega$ and the inclination $I$ of an artificial satellite of the spinning Earth ... More
Scale dependence of energy transfer in turbulent plasmaSep 15 2018In the context of space and astrophysical plasma turbulence and particle heating, several vocabularies emerge for estimating turbulent energy dissipation rate, including Kolmogorov-Yaglom third-order law and, in its various forms, $\boldsymbol{j}\cdot\boldsymbol{E}$ ... More
A frequency portrait of Low Earth OrbitsSep 13 2018In this work we deepen and complement the analysis on the dynamics of Low Earth Orbits (LEO), carried out by the authors within the H2020 ReDSHIFT project, by characterising the evolution of the eccentricity of a large set of orbits in terms of the main ... More
Measuring the De Sitter precession with a new Earth's satellite to the $\mathbf{\simeq 10^{-5}}$ level: a proposalSep 05 2018Jan 16 2019The inclination $I$ of an Earth's satellite in polar orbit undergoes a secular De Sitter precession of $-7.6$ milliarcseconds per year for a suitable choice of the initial value of its non-circulating node $\Omega$. The competing long-periodic harmonic ... More
Effects of neutrino mixing upon electron fraction in core collapse supernovaeSep 04 2018Sep 06 2018The inclusion of massive neutrinos affects the cross sections involved in the formation of heavy nuclei, modifying their abundances. Rapid neutron capture processes (r-process) are often associated with explosive events such as core-collapse supernovae. ... More
On the Role of Separatrix Instabilities in Heating the Reconnection Outflow RegionAug 29 2018A study of the role of microinstabilities at the reconnection separatrix can play in heating the electrons during the transition from inflow to outflow is being presented. We find that very strong flow shears at the separatrix layer lead to counterstreaming ... More
Using the maximum entropy distribution to describe electrons in reconnecting current sheetsAug 23 2018Particle distributions in weakly collisional environments such as the magnetosphere have been observed to show deviations from the Maxwellian distribution. These can often be reproduced in kinetic simulations, but fluid models, which are used in global ... More
Globally Distributed Energetic Neutral Atom Maps for the "Croissant" HeliosphereAug 17 2018A recent study by Opher et al. (2015) suggested the heliosphere has a "croissant" shape, where the heliosheath plasma is confined by the toroidal solar magnetic field. The "croissant" heliosphere is in contrast to the classically accepted view of a comet-like ... More
Vlasov methods in space physics and astrophysicsAug 17 2018This paper reviews Vlasov-based numerical methods used to model plasma in space physics and astrophysics. Plasma consists of collectively behaving charged particles that form the major part of baryonic matter in the Universe. Many concepts ranging from ... More
MARSIS observations of field-aligned irregularities and ducted radio propagation in the Martian ionosphereAug 15 2018Knowledge of Mars's ionosphere has been significantly advanced in recent years by observations from Mars Express (MEX) and lately MAVEN. A topic of particular interest are the interactions between the planet's ionospheric plasma and its highly structured ... More
Investigation of energetic particle release using multi-point imaging and in situ observationsAug 15 2018The solar eruption on 2012 January 27 resulted in a wide-spread solar energetic particle (SEP) event observed by STEREO A and the near-Earth spacecraft (separated by 108\degree). The event was accompanied by an X-class flare, extreme-ultraviolet (EUV) ... More
Fluidization of collisionless plasma turbulenceAug 13 2018In a collisionless, magnetized plasma, particles may stream freely along magnetic-field lines, leading to phase "mixing" of their distribution function and consequently to smoothing out of any "compressive" fluctuations (of density, pressure, etc.,). ... More
How accurately can we measure the reconnection rate $E_M$ for the MMS diffusion region event of 2017-07-11?Aug 10 2018We investigate the accuracy with which the reconnection electric field $E_M$ can be determined from in-situ plasma data. We study the magnetotail electron diffusion region observed by NASA's Magnetospheric Multiscale (MMS) on 2017-07-11 at 22:34 UT and ... More