The PAC2MAN mission: a new tool to understand and predict solar energetic events

An accurate forecast of flare and CME initiation requires precise measurements of the magnetic energy build up and release in the active regions of the solar atmosphere. We designed a new space weather mission that performs such measurements using new optical instruments based on the Hanle and Zeeman effects. The mission consists of two satellites, one orbiting the L1 Lagrangian point (Spacecraft Earth, SCE) and the second in heliocentric orbit at 1AU trailing the Earth by 80$^\circ$ (Spacecraft 80, SC80). Optical instruments measure the vector magnetic field in multiple layers of the solar atmosphere. The orbits of the spacecraft allow for a continuous imaging of nearly 73\% of the total solar surface. In-situ plasma instruments detect solar wind conditions at 1AU and ahead of our planet. Earth directed CMEs can be tracked using the stereoscopic view of the spacecraft and the strategic placement of the SC80 satellite. Forecasting of geoeffective space weather events is possible thanks to an accurate surveillance of the magnetic energy build up in the Sun, an optical tracking through the interplanetary space, and in-situ measurements of the near-Earth environment.Comment: Accepted for publication in the Journal of Space Weather and Space Climate (SWSC

The PAC2MAN mission: A new tool to understand and predict solar energetic events

An accurate forecast of flare and coronal mass ejection (CME) initiation requires precise measurements of the magnetic energy buildup and release in the active regions of the solar atmosphere. We designed a new space weather mission that performs such measurements using new optical instruments based on the Hanle and Zeeman effects. The mission consists of two satellites, one orbiting the L1 Lagrangian point (Spacecraft Earth, SCE) and the second in heliocentric orbit at 1AU trailing the Earth by 80° (Spacecraft 80, SC80). Optical instruments measure the vector magnetic field in multiple layers of the solar atmosphere. The orbits of the spacecraft allow for a continuous imaging of nearly 73% of the total solar surface. In-situ plasma instruments detect solar wind conditions at 1AU and ahead of our planet. Earth-directed CMEs can be tracked using the stereoscopic view of the spacecraft and the strategic placement of the SC80 satellite. Forecasting of geoeffective space weather events is possible thanks to an accurate surveillance of the magnetic energy buildup in the Sun, an optical tracking through the interplanetary space, and in-situ measurements of the near-Earth environment

Plasma Imaging, LOcal Measurement, and Tomographic experiment (PILOT): a mission concept for transformational multi-scale observations of mass and energy flow dynamics in Earth’s magnetosphere

We currently do not understand the fundamental physical processes that govern mass and energy flow through the Earth’s magnetosphere. Knowledge of these processes is critical to understanding the mass loss rate of Earth’s atmosphere, as well as for determining the role that a planetary magnetic field plays in atmospheric retention, and therefore habitability, for Earth-like planets beyond the solar system. Mass and energy flow processes are challenging to determine at Earth in part because Earth’s planetary magnetic field creates a complex “system of systems” composed of interdependent plasma populations and overlapping spatial regions that perpetually exchange mass and energy across a broad range of temporal and spatial scales. Further, the primary mass carrier in the magnetosphere is cold plasma (as cold as ∼0.1 eV), which is invisible to many space-borne instruments that operate in the inner magnetosphere. The Plasma Imaging LOcal and Tomographic experiment (PILOT) mission concept, described here, provides the transformational multi-scale observations required to answer fundamental open questions about mass and energy flow dynamics in the Earth’s magnetosphere. PILOT uses a constellation of spacecraft to make radio tomographic, remote sensing, and in-situ measurements simultaneously, fully capturing cold plasma mass dynamics and its impact on magnetospheric systems over an unprecedented range of spatial and temporal scales. This article details the scientific motivation for the PILOT mission concept as well as a potential mission implementation.AGS-1845151 - National Science FoundationPublished versio

Modeling the radial diffusion process in the Earth's radiation belts by a scale-changing technique

Cette étude s’inscrit dans le domaine de la description de la dynamique des ceintures deradiation terrestres. Elle consiste à modéliser le phénomène de diffusion radiale en travaillantavec une résolution spatio-temporelle plus fine que celle utilisée pour décrire la dynamiquedes ceintures par le biais d’une équation de diffusion. La démarche s’est organisée en troistemps. Tout d’abord, l’objectif a été d’étudier le phénomène de diffusion radiale d’un point devue théorique afin de mettre en lumière les principaux pilotes du processus et d’expliciter uneformulation des coefficients de diffusion radiale. Une fois l’expression de ces coefficientsétablie, l’objectif a ensuite été de les quantifier. Pour cela, nous avons développé desprotocoles analytiques et numériques puis des protocoles expérimentaux. Nous avons discutéles résultats obtenus ainsi que les atouts et les limites de ces protocoles. Cette étude met enévidence le rôle central de l’asymétrie des variations du champ électromagnétique et deschamps électriques induits dans le processus de diffusion radiale. Elle propose des pistes pourla quantification numérique et expérimentale de ces deux pilotes. Elle apporte également unregard critique sur les travaux de la littérature. Elle ouvre la voie pour une nouvellequantification des coefficients de diffusion basée sur une modélisation adéquate de ladynamique de l’environnement électromagnétiqueThis study falls within the field of the Earth’s radiation belt dynamics. It consists of modelingthe radial diffusion process based on a spatiotemporal resolution higher than the resolution atwhich radiation belt dynamics are described in terms of a diffusion equation. The approachhas been organized in three parts. First, we described radial diffusion theoretically,highlighting the main drivers of the phenomenon and giving a ready-made formula of theradial diffusion coefficients. Then, based on this formula, we aimed to quantify the radialdiffusion coefficients. In order to reach this goal, we developed analytical and numericalprocedures, and then, observational procedures. Finally, we discussed the results and the prosand cons of each method. This study highlights the central role of asymmetric variations ofthe electromagnetic fields and induced electric fields in the driving of the intensity of theradial diffusion process. It provides tracks for numerical and experimental quantification ofthese two drivers. It also provides tools for a critical review of the literature. It paves the wayfor a more accurate determination of radial diffusion coefficients based on a more precisedescription of the electromagnetic environment and its variations

Shorting Factor In‐Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere

Satellite-based direct electric field measurements deliver crucial information for space science studies. Yet, they require meticulous design and calibration. In-flight calibration of double-probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf ). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly exceeds any geophysical electric field of interest in the plasmasphere. Thus, the highest level of accuracy in calibration is required. The objective of this work is to discuss the accuracy of the setting Sf =1 and therefore to examine the accuracy of Van Allen Probes electric field measurements below L = 2. We introduce a method to determine the shorting factor near perigee. It relies on the idea that the value of the geophysical electric field measured in the Earth's rotating frame of reference is independent of whether the spacecraft is approaching perigee or past perigee, i.e. it is independent of spacecraft velocity. We obtain that Sf =0.994 ± 0.001. The resulting margins of errors in individual electric drift measurements are of the order of ± 0.1% of spacecraft velocity (a few meters per second)

Shorting Factor In‐Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere

Satellite-based direct electric field measurements deliver crucial information for space science studies. Yet, they require meticulous design and calibration. In-flight calibration of double-probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf ). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly exceeds any geophysical electric field of interest in the plasmasphere. Thus, the highest level of accuracy in calibration is required. The objective of this work is to discuss the accuracy of the setting Sf =1 and therefore to examine the accuracy of Van Allen Probes electric field measurements below L = 2. We introduce a method to determine the shorting factor near perigee. It relies on the idea that the value of the geophysical electric field measured in the Earth's rotating frame of reference is independent of whether the spacecraft is approaching perigee or past perigee, i.e. it is independent of spacecraft velocity. We obtain that Sf =0.994 ± 0.001. The resulting margins of errors in individual electric drift measurements are of the order of ± 0.1% of spacecraft velocity (a few meters per second)

PAC2MAN: Photospheric And Chromospheric and Coronal Magnetic field ANalyser

International audienc

PAC2MAN: Photospheric And Chromospheric and Coronal Magnetic field ANalyser

International audienc