A5082091157- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Cardiac Arrhythmias and Treatments
- Venous Thromboembolism Diagnosis and Management
- Astro and Planetary Science
- Cardiac Imaging and Diagnostics
- Stellar, planetary, and galactic studies
- Infective Endocarditis Diagnosis and Management
- Geophysics and Gravity Measurements
- Cardiovascular Syncope and Autonomic Disorders
- Pulsars and Gravitational Waves Research
- Pericarditis and Cardiac Tamponade
- Neurological Disorders and Treatments
- Atrial Fibrillation Management and Outcomes
- Gamma-ray bursts and supernovae
- Lipoproteins and Cardiovascular Health
- Diphtheria, Corynebacterium, and Tetanus
- Cardiac tumors and thrombi
- Myasthenia Gravis and Thymoma
- Cardiac electrophysiology and arrhythmias
- Hematological disorders and diagnostics
- Metabolism and Genetic Disorders
- Cardiac Valve Diseases and Treatments
- Heparin-Induced Thrombocytopenia and Thrombosis
- Potassium and Related Disorders
Université Paris Cité
2020-2025
Astrophysique, Instrumentation et Modélisation
2017-2025
Centre National de la Recherche Scientifique
2013-2025
CEA Paris-Saclay
2017-2025
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2017-2025
Université Paris-Saclay
2020-2025
Institut de Recherche sur les Lois Fondamentales de l'Univers
2017-2022
Délégation Paris 7
2020
Sorbonne Paris Cité
2020
Université de Lorraine
2020
The release of spin-down energy by a magnetar is promising scenario to power several classes extreme explosive transients. However, it lacks firm basis because formation still represents theoretical challenge. Using the first three-dimensional simulations convective dynamo based on protoneutron star interior model, we demonstrate that required dipolar magnetic field can be consistently generated for sufficiently fast rotation rates. instability saturates in magnetostrophic regime with...
Magnetars are highly magnetized neutron stars whose magnetic dipole ranges from $10^{14}$ to $10^{15}$ G. The MRI is considered be a promising mechanism amplify the field in fast-rotating protoneutron and form magnetars. This scenario supported by many local studies showing that fields could amplified on small scales. However, efficiency of at generating still unknown. To answer this question, we study dynamo an idealized global model fast rotating star with differential rotation. We perform...
Magnetars are highly magnetized neutron stars that can produce X-ray and soft gamma-ray emissions have a dipole of $10^{14}$ G to $10^{15}$ G. A promising mechanism for explaining magnetar formation is magnetic field amplification by the MRI in fast-rotating protoneutron (PNS). This scenario supported recent global models, which showed small-scale turbulence generate with magnetar-like intensity. However, impact buoyancy density stratification on efficiency generating still unknown. We...
Magnetars are isolated young neutron stars characterized by the most intense magnetic fields known in universe. The origin of their field is still a challenging question. In situ amplification dynamo action promising process to generate ultra-strong fast-rotating progenitors. However, it unclear whether fraction progenitors harboring fast core rotation sufficient explain entire magnetar population. To address this point, we propose new scenario for formation, which slow-rotating...
The formation of highly magnetized young neutron stars, called magnetars, is still a strongly debated topic. One promising scenario invokes the amplification magnetic field by Tayler-Spruit dynamo in proto-neutron star (PNS) that spun up fall-back. Our previous numerical study supports this demonstrating can generate magnetar-like fields stably stratified Boussinesq models PNS interior. To further investigate dynamo, we performed 3D magnetohydrodynamic (MHD) simulations with MagIC code,...
We consider dynamo action driven by three-dimensional rotating anelastic convection in a spherical shell. Motivated the behaviour of solar dynamo, we examine interaction hydromagnetic modes with different symmetries and demonstrate how complicated interactions between convection, differential rotation magnetic fields may lead to modulation basic cycle. For some parameters, Type 1 occurs transfer energy little change overall amplitude, for other is 2, where amplitude significantly affected...
The dynamo driven by the magnetorotational instability (MRI) is believed to play an important role in dynamics of accretion discs and may also explain origin extreme magnetic fields present magnetars. Its saturation level open question known be particularly sensitive diffusive processes through Prandtl number Pm (the ratio viscosity resistivity). Despite its relevance proto-neutron stars neutron star merger remnants, numerically challenging regime high still largely unknown. Using zero-net...
Observations of low-mass stars reveal a variety magnetic field topologies ranging from large-scale, axial dipoles to more complex fields. At the same time, three-dimensional spherical simulations convectively driven dynamos reproduce similar diversity, which is commonly obtained either with Boussinesq models or realistic based on anelastic approximation, take into account variation density depth throughout convection zone. Nevertheless, conclusion different studies that dipolar solutions...
Gravitational waves provide a unique and powerful opportunity to constrain the dynamics in interior of proto-neutron stars during core collapse supernovae. Convective motions play an important role generating neutron magnetic fields, which could explain magnetar formation presence fast rotation. We compute gravitational wave emission from star convection its associated dynamo, by post-processing three-dimensional MHD simulations model restricted convective zone anelastic approximation....
Abstract Core-collapse supernovae (CCSNe) offer extremely valuable insights into the dynamics of galaxies. Neutrino time profiles from CCSNe, in particular, could reveal unique details about collapsing stars and particle behavior dense environments. However, CCSNe our galaxy Large Magellanic Cloud are rare only one supernova neutrino observation has been made so far. To maximize information obtained next Galactic CCSN, it is essential to combine analyses multiple experiments real transmit...
Context. Three-dimensional spherical dynamo simulations carried out within the framework of anelastic approximation have revealed that established distinction between dipolar and multipolar dynamos tends to be less clear than it was in Boussinesq studies. This result first interpreted as a direct consequence existence larger number models with high equatorial dipole contribution, together an intermediate field strength. However, this finding has not been clearly related specific changes...
Numerical modelling of convection driven dynamos in the Boussinesq approximation revealed fundamental characteristics dynamo-generated magnetic fields and fluid flow. Because these results were obtained for an incompressible fluid, their validity gas planets stars remains to be assessed. A common approach is take some density stratification into account with so-called anelastic approximation. The previous tested models. We point out explain specific differences between both types models,...
ABSTRACT The Tayler–Spruit dynamo is one of the most promising mechanisms proposed to explain angular momentum transport during stellar evolution. Its development in proto-neutron stars spun-up by supernova fallback has also been put forward as a scenario formation very magnetized neutron called magnetars. Using three-dimensional direct numerical simulations, we model star interior stably stratified spherical Couette flow with outer sphere that rotates faster than inner one. We report...
We investigate dynamo action in three-dimensional numerical simulations of turbulent spherical Couette flows. Close to the onset action, magnetic field exhibits an intermittent behavior, characterized by a series short bursts energy separated low-energy phases. show that this behavior corresponds so-called on-off intermittency. This is here reported for with realistic boundary conditions. role conditions phenomenon.
Recent interferometric data have been used to constrain the brightness distribution at surface of nearby stars, in particular so-called gravity darkening that makes fast rotating stars brighter their poles than equator. However, good models are missing for posses a convective envelope. In order better understand how rotation affects heat transfer stellar envelopes, we focus on flux latitude outer numerical models. We carry out systematic parameter study three-dimensional, direct simulations...