Tootfinder

Unified understanding of Alfv\'enic superradiance and the Blandford-Znajek process in a force-free black hole magnetosphere
Sousuke Noda, Masaaki Takahashi
https://arxiv.org/abs/2508.04771

Unified understanding of Alfvénic superradiance and the Blandford-Znajek process in a force-free black hole magnetosphere
We investigate the extraction of energy from a Kerr black hole via Alfvén waves (i.e., Alfvénic superradiance) in a force-free magnetosphere, in which the plasma inertia effects are ignored. We analyze the Poynting flux generated by Alfvén waves that propagate toward the event horizon across the inner light surface, the causal boundary for the waves. We find the relationship between the energy flux associated with Alfvén waves and that of the Blandford-Znajek (BZ) process. That is, both mec…

Whistler Chorus Amplification in the Magnetosphere: A Nonlinear Free-Electron Laser Model Based on the Ginzburg-Landau Equation
Brandon Bonham, Amitava Bhattacharjee
https://arxiv.org/abs/2506.06167

Whistler Chorus Amplification in the Magnetosphere: A Nonlinear Free-Electron Laser Model Based on the Ginzburg-Landau Equation
We present a novel nonlinear model for whistler-mode chorus amplification based on the free-electron laser (FEL) mechanism. First, we derive the nonlinear collective variable equations for the whistler-electron interaction. Consistent with in situ satellite observations, these equations predict that a small seed wave can undergo exponential growth, reaching a peak of a few hundred picoteslas after a few milliseconds, followed by millisecond timescale amplitude modulations. Next, we show that wh…

Gravitational waves in minimal Maxwell $f(R)$ gravity
Salvatore Capozziello, Qingyu Gan
https://arxiv.org/abs/2507.06094 https://arxi…

Gravitational waves in minimal Maxwell $f(R)$ gravity
We discuss the conversion mechanism from scalar field to gravitational waves in magnetic background in $f(R)$ gravity minimal coupled to the Maxwell electrodynamics. Applying the conversion in early universe with primordial magnetic field and the neutron star with strong magnetosphere, the generated gravitational waves, converted from the scalar field, exhibit distinct power spectra which can be potentially probed by future experiments such as DECIGO, BBO, CE and ET.

Jupiter's UV auroral response to a magnetospheric compression event: #Juno spacecraft data suggest an extreme compression of the planet’s magnetosphere in December 2022, caused by the solar wind, briefly brightened the ultraviolet light displays.

YSO Jets Driven by Magnetic Pressure Generated through Stellar Magnetosphere-Disk Interaction
Yisheng Tu, Zhi-Yun Li, Zhaohuan Zhu, Xiao Hu, Chun-Yen Hsu
https://arxiv.org/abs/2506.11333

YSO Jets Driven by Magnetic Pressure Generated through Stellar Magnetosphere-Disk Interaction
The origin of jets in young stellar objects (YSOs) remains a subject of active investigation. We present a 3D non-ideal magnetohydrodynamic simulation of jet launching in YSOs, focusing on the interaction between the stellar magnetosphere and the circumstellar disk. At the beginning of the simulation, the magnetosphere partially opens, forming two oppositely directed magnetic field regions: one threading the star and the other threading the inner disk. The latter dominates over the original dis…

Energetic ($< 2$ MeV) Ion Environment of the Magnetosphere as measured by ASPEX-STEPS on board Aditya-L1 during its earth-bound phase
Dibyendu Chakrabarty, Bijoy Dalal, Santosh Vadawale, Aveek Sarkar, Shiv Kumar Goyal, Jacob Sebastian, Anil Bhardwaj, P. Janardhan, M. Shanmugam, Neeraj Kumar Tiwari, Aaditya Sarda, Piyush Sharma, Aakash Gupta, Prashant Kumar, Manan S. Shah, Bhas Bapat, Pranav R Adhyaru, Arpit R. Patel, Hitesh Kumar Adalja, Abhishek Kumar, Tinkal Ladiya, Sushil Kumar, …

Energetic ($< 2$ MeV) Ion Environment of the Magnetosphere as measured by ASPEX-STEPS on board Aditya-L1 during its earth-bound phase
During its earth-bound phase of the Aditya-L1 spacecraft of India, the Supra-Thermal and Energetic Particle Spectrometer (STEPS) of the Aditya Solar wind Particle EXperiment (ASPEX) was operated whenever the orbit was above 52000 km during 11-19 September 2023. This phase of operation provided measurements of energetic ions (with energies 0.1-2 MeV) in the magnetosphere, magnetosheath, and interplanetary medium. Three interplanetary coronal mass ejections (ICME) hit the magnetosphere during thi…

Direct Measurement of Electron Heating in Electron-Only Reconnection in a Laboratory Mini-Magnetosphere
Lucas Rovige, Filipe D. Cruz, Timothy Van Hoomisen, Robert S. Dorst, Carmen G. Constantin, Stephen Vincena, Luis O. Silva, Christoph Niemann, Derek B. Schaeffer
https://arxiv.org/abs/2508.09086

Direct Measurement of Electron Heating in Electron-Only Reconnection in a Laboratory Mini-Magnetosphere
We report on the experimental observation of electron heating in electron-only magnetic reconnection in laser-driven laboratory mini-magnetospheres on the Large Plasma Device (LAPD) at the University of California, Los Angeles. In this experiment, a fast-flowing plasma impacts a pulsed magnetic dipole embedded within LAPD's magnetized ambient plasma, creating an ion-scale magnetosphere and driving electron-only magnetic reconnection between the background and dipole field lines. The electron ve…

Nanosatellites for the study of high-energy particles$'$ microbursts$'$ nature in the Earth$'$s magnetosphere: an idea of cosmic experiment
O. V. Dudnik, E. V. Kurbatov
https://arxiv.org/abs/2506.22798

Nanosatellites for the study of high-energy particles$'$ microbursts$'$ nature in the Earth$'$s magnetosphere: an idea of cosmic experiment
A concept of a cosmic scientific experiment is presented. The main goal of the experiment is the study of miscrobursts of charged particles of high energy in the Earth$'$s magnetosphere. The experiment is designed to use a nanosatellite platform. The paper describes the functional scheme, structural features and technical characteristics of a miniature detector-analyser of electrons and protons, MiRA$\_$ep. Keywords: radiation belt, electron, nanosatellite, silicon detector, organic scintillato…

Crustal Quakes Spark Magnetospheric Blasts: Imprints of Realistic Magnetar Crust Oscillations on the Fast Radio Burst Signal
Louis Burnaz, Elias R. Most, Ashley Bransgrove
https://arxiv.org/abs/2508.18033

Crustal Quakes Spark Magnetospheric Blasts: Imprints of Realistic Magnetar Crust Oscillations on the Fast Radio Burst Signal
Many transients believed to originate from magnetars are thought to be triggered by crustal activity, which feeds back on the surrounding magnetosphere. These perturbations, through a variety of proposed mechanisms, can convert a fraction of the magnetic energy stored in the magnetosphere, as well as the energy injected by crustal activity itself into electromagnetic emission, including X-ray bursts and fast radio bursts. Here we provide a first glimpse of this process by coupling magneto-elast…

A half-ring of ionized circumstellar material trapped in the magnetosphere of a white dwarf merger remnant
Andrei A. Cristea, Ilaria Caiazzo, Tim Cunningham, John C. Raymond, Stephane Vennes, Adela Kawka, Aayush Desai, David R. Miller, J. J. Hermes, Jim Fuller, Jeremy Heyl, Jan van Roestel, Kevin B. Burdge, Antonio C. Rodriguez, Ingrid Pelisoli, Boris T. G\"ansicke, Paula Szkody, Scott J. Kenyon, Zach Vanderbosch, Andrew Drake, Lilia Ferrario, Dayal Wickramasinghe, Viraj R. Karamb…

A half-ring of ionized circumstellar material trapped in the magnetosphere of a white dwarf merger remnant
Many white dwarfs are observed in compact double white dwarf binaries and, through the emission of gravitational waves, a large fraction are destined to merge. The merger remnants that do not explode in a Type Ia supernova are expected to initially be rapidly rotating and highly magnetized. We here present our discovery of the variable white dwarf ZTF J200832.79+444939.67, hereafter ZTF J2008+4449, as a likely merger remnant showing signs of circumstellar material without a stellar or substella…

On the Fast-radio-burst-associated X-ray Bursts: Inverse Compton Scattering of Radio Photons by an Extreme Pair Flow During Magnetosphere Activities
Yue Wu, Yuan-Pei Yang, Fa-Yin Wang, Zi-Gao Dai
https://arxiv.org/abs/2507.12405

On the Fast-radio-burst-associated X-ray Bursts: Inverse Compton Scattering of Radio Photons by an Extreme Pair Flow During Magnetosphere Activities
The Galactic fast radio burst (FRB) FRB 200428 was associated with a short X-ray burst (XRB) from the magnetar SGR J1935+2154 during one of its active phases. This FRB-associated XRB exhibits distinct properties compared to other typical XRBs, including a significantly higher cutoff energy and a steeper power-law index. Its recovered X-ray light curve shows a multiple-peak structure, with the time of arrival offset from that of the FRB. These unique features imply a special physical link betwee…

Phase-Space Synchronization Driven by Moon-Magnetosphere Coupling in Gas Giants
Adnane Osmane, Elias Roussos, Peter Kollmann
https://arxiv.org/abs/2507.07739

Phase-Space Synchronization Driven by Moon-Magnetosphere Coupling in Gas Giants
We present a new theoretical framework to describe the rapid and spatially localized loss of energetic particles in planetary radiation belts, focusing on interactions between gas giant magnetospheres and their moons. Observations show that flux depletions--known as microsignatures--often refill on timescales comparable to a single drift period, which conflicts with traditional quasi-linear radial diffusion models that assume slow, gradual transport and predict refilling only over many drift pe…

$\boldsymbol{\nabla} \boldsymbol{\cdot} \mathbf{B}$, outer boundary, and Biot-Savart in magnetosphere MHD simulations
Dean Thomas (Space Weather Lab, Department of Physics and Astronomy, George Mason University, Fairfax, VA, USA), Robert S. Weigel (Space Weather Lab, Department of Physics and Astronomy, George Mason University, Fairfax, VA, USA), Gary Quaresima (Department of Physics, University of Virginia, Charlottesville, VA, USA), Antti Pulkkinen (Heliophysics Science Division, NAS…

$\boldsymbol{\nabla} \boldsymbol{\cdot} \mathbf{B}$, outer boundary, and Biot-Savart in magnetosphere MHD simulations
We examine the size of $\boldsymbol{\nabla} \boldsymbol{\cdot} \mathbf{B}$ and outer surface boundary integrals in estimating the surface magnetic field from magnetohydrodynamic (MHD) simulations. Maxwell's equations tell us $\boldsymbol{\nabla} \boldsymbol{\cdot} \mathbf{B}$ = 0, which may be violated due to numerical error. MHD models, such as the Space Weather Modeling Framework (SWMF) and the Open Geospace General Circulation Model (OpenGGCM), use different techniques to limit $\boldsymbol{…

Relativistic van Allen belts in magnetospheres of pulsars and white dwarfs
Maxim V. Barkov, Maxim Lyutikov
https://arxiv.org/abs/2506.20515 https://…

Relativistic van Allen belts in magnetospheres of pulsars and white dwarfs
We consider dynamics and multi-frequency emission patterns of relativistic van Allen belts - particles trapped in the magnetosphere of neutron stars and white dwarths. We account for synchrotron radiative losses and effects of relativistic beaming of radiation. The system is non-Hamiltonian (non-energy conserving): this results in a wide non-scalable variety of spectral and temporal behaviors. There are three types of trapped particles' trajectories: (i) oscillating (particles experience mult…

Large Model Driven Solar Activity AI Forecaster: A Scalable Dual Data-Model Framework
Jingjing Wang, Pengyu Liang, Tingyu Wang, Ming Li, Yanmei Cui, Siwei Liu, Xin Huang, Xiang Li, Minghui Zhang, Yunshi Zeng, Zhu Cao, Jiekang Feng, Qinghua Hu, Bingxian Luo, Bing Cao
https://arxiv.org/abs/2508.06892…

Large Model Driven Solar Activity AI Forecaster: A Scalable Dual Data-Model Framework
Solar activity drives space weather, affecting Earth's magnetosphere and technological infrastructure, which makes accurate solar flare forecasting critical. Current space weather models under-utilize multi-modal solar data, lack iterative enhancement via expert knowledge, and rely heavily on human forecasters under the Observation-Orientation-Decision-Action (OODA) paradigm. Here we present the "Solar Activity AI Forecaster", a scalable dual data-model driven framework built on foundational mo…

Gamma-ray Pulsar Emission is Mostly Stable on Timescales from Minutes to Years
Matthew Kerr
https://arxiv.org/abs/2508.18195 https://arxiv.org/pdf/2508.181…

Gamma-ray Pulsar Emission is Mostly Stable on Timescales from Minutes to Years
We present a method for the detection and characterization of random changes in the flux from $γ$-ray pulsars on sub-hour timescales, much shorter than variations that can be accessed using direct flux measurements. Flux variations are a proxy for the variations in spindown power ($\dot{E}$) or particle acceleration, which can be produced by random switches between quasi-stable configurations of the pulsar magnetosphere. This technique therefore probes the stability of pulsar magnetospheres an…

Evidence of the Earth's inner radiation belts during the low Solar and geomagnetic activity obtained with the STEP-F instrument
O. V. Dudnik, O. V. Yakovlev
https://arxiv.org/abs/2506.21218

Evidence of the Earth's inner radiation belts during the low Solar and geomagnetic activity obtained with the STEP-F instrument
Purpose: The subject of research is the spatio-temporal charged particles in the Earth's magnetosphere outside the South Atlantic magnetic Anomaly during the 11-year cycle of solar activity minimum. The work aims at searching for and clarifying the sustained and unstable new spatial zones of enhanced subrelativistic electron fluxes at the altitudes of the low Earth orbit satellites. Design/methodology/approach: Finding and ascertainment of new radiation belts of the Earth were made by using t…

Extreme Solar Storm Reveals Causal Interactions in Space Weather
Xinan Dai, Haiyang Fu, Zichong Yan, Zitong Wang, Feng Xu, Chi Wang, Yuhong Liu, YaQiu Jin
https://arxiv.org/abs/2508.06507

Extreme Solar Storm Reveals Causal Interactions in Space Weather
Solar storms perturb Earth's magnetosphere, triggering geomagnetic storms that threaten space-based systems and infrastructure. Despite advances in spaceborne and ground-based observations, the causal chain driving solar-magnetosphere-ionosphere dynamics remains elusive due to multiphysics coupling, nonlinearity, and cross-scale complexity. This study presents an information-theoretic framework to decipher interaction mechanisms in extreme solar geomagnetic storms across intensity levels within…

Three-Dimensional Numerical Simulations of Magnetar Crust Quakes
Yuanhong Qu, Ashley Bransgrove
https://arxiv.org/abs/2508.12567 https://arxiv.org/pdf/2508…

Three-Dimensional Numerical Simulations of Magnetar Crust Quakes
Crust quakes are frequently invoked as a mechanism to trigger sudden transients in the magnetospheres of magnetars. In this picture, a mechanical failure of the crust excites seismic motions of the magnetar surface that launch force-free waves into the magnetosphere. We first investigate this problem analytically and then perform three-dimensional numerical simulations. Our simulations follow the propagation of high-frequency magneto-elastic waves in the entire crust, and include magnetic coupl…

Ultra-luminous X-ray pulsars as sources of TeV neutrinos
L. Ducci, E. Perinati, P. Romano, S. Vercellone, M. Niko{\l}ajuk, A. Santangelo, M. Sasaki
https://arxiv.org/abs/2508.10487

Ultra-luminous X-ray pulsars as sources of TeV neutrinos
We explored the expected properties of the neutrino emission from accreting neutron stars in X-ray binaries using numerical simulations. The simulations are based on a model in which neutrinos are produced by the decay of charged pions and kaons, generated in inelastic collisions between protons accelerated up to TeV energies in the magnetosphere of a magnetized (B~1E12 G) neutron star and protons of the accretion disc. Our results show that this process can produce strong neutrino emission up …

This https://arxiv.org/abs/2405.02199 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Alfvén Wave Conversion to Low Frequency Fast Magnetosonic Waves in Magnetar Magnetospheres
Rapid shear motion of magnetar crust can launch Alfvén waves into the magnetosphere. The dissipation of the Alfvén waves has been theorized to power the X-ray bursts characteristic of magnetars. However, the process by which Alfvén waves convert their energy to X-rays is unclear. Recent work has suggested that energetic fast magnetosonic (fast) waves can be produced as a byproduct of Alfvén waves propagating on curved magnetic field lines; their subsequent dissipation may power X-ray bursts…

Replaced article(s) found for physics.space-ph. https://arxiv.org/list/physics.space-ph/new
[1/1]:
- Whistler Chorus Amplification in the Magnetosphere: The Nonlinear Free-Electron Laser Model and t...
Brandon Bonham, Amitava Bhattacharjee

Planar Collisionless Shock Simulations with Semi-Implicit Particle-in-Cell Model FLEKS
Hongyang Zhou, Yuxi Chen, Chuanfei Dong, Liang Wang, Ying Zou, Brian Walsh, G\'abor T\'oth
https://arxiv.org/abs/2506.08384

Planar Collisionless Shock Simulations with Semi-Implicit Particle-in-Cell Model FLEKS
This study investigates the applicability of the semi-implicit particle-in-cell code FLEKS to collisionless shock simulations, with a focus on the parameter regime relevant to global magnetosphere modeling. We examine one- and two-dimensional local planar shock simulations, initialized using MHD states with upstream conditions representative of the solar wind at 1 au, for both quasi-perpendicular and quasi-parallel configurations. The refined algorithm in FLEKS proves robust, enabling accurate …