physics.space-ph

Electron Heat Flux and Whistler Instability in the Earth's Magnetosheath

Using MMS in situ measurements, this study demonstrates that electron heat flux in the Earth's magnetosheath is primarily shaped by the draping of the magnetic field and solar wind conditions rather than local processes, and is ultimately limited by whistler instability thresholds.

Multi-Fidelity Monte-Carlo Estimation of Satellite Drag in Very-Low-Earth Orbit

This paper proposes a multi-fidelity Monte Carlo (MFMC) estimator that uses low-fidelity panel methods as control variates to significantly reduce the computational cost of quantifying drag coefficient uncertainty and higher-order moments for satellites in very-low-Earth orbit compared to using high-fidelity DSMC solvers alone.

Radial evolution of Alfvén wave Parametric Decay Instability in the near-Sun solar wind: Effects of Temperature Anisotropy

This paper investigates how temperature anisotropy affects the growth rates of Alfvén wave parametric decay instability (PDI) in the near-Sun solar wind using CGL equations, finding that perpendicular anisotropy significantly enhances PDI in low-$\beta$ regimes.

Observation of a Knotted Electron Diffusion Region in Earth's Magnetotail Reconnection

Using Magnetospheric Multiscale (MMS) mission data, this study reports the first observation of a non-coplanar, knotted electron diffusion region in Earth's magnetotail that deviates significantly from the ion diffusion region, revealing complex three-dimensional effects and multiscale coupling during magnetic reconnection.

Spectral Properties and Energy Injection in Mercury's Magnetotail Current Sheet

This study analyzes MESSENGER magnetic field data from 370 Mercury magnetotail current sheets to reveal that most events exhibit turbulent spectra with a dawn-dusk asymmetry, where the dawnside shows more developed turbulence and energy injection occurring at ion scales rather than within a classical inertial range.

Properties and Radial Evolution of Solar Wind Turbulence Near Mercury's Orbit

This study analyzes over 17,000 hours of MESSENGER magnetic field data to reveal that while solar wind turbulence near Mercury's orbit maintains a stable, Alfvénic inertial range, its kinetic scales exhibit significant radial evolution characterized by shallower spectral slopes and increasing compressibility as heliocentric distance increases.

Collisionless Phase Mixing Mimics Diffusive Transport in Radiation Belt Observations

Europa's Lyman-$\alpha$ emissions from HST/STIS observations

This study reanalyzes Hubble Space Telescope observations of Europa's Lyman-$\alpha$ emissions from 1999 to 2020, confirming a global atomic hydrogen exosphere with a temperature of approximately 1000 K while finding no evidence for the localized water vapor aurora previously reported, attributing the earlier discrepancy to errors in detector positioning and the omission of the exospheric signal.

Polytropic stellar wind models with strongly localized heating

This paper generalizes polyropic stellar wind models to include more realistic non-adiabatic behavior under strongly localized heating, demonstrating that the required energy is plausible and offering potential explanations for variable wind streams and acoustic waves observed by the Parker Solar Probe.

A Neural-Network Framework for Tracking and Identification of Cosmic-Ray Nuclei in the RadMap Telescope

This paper presents a neural-network framework utilizing Geant4 simulations to reconstruct cosmic-ray nuclei properties in the RadMap Telescope, achieving high angular resolution, charge separation accuracy (up to 99.8% for hydrogen), and energy resolution (<20% below 1 GeV/n) to enable precise determination of astronaut radiation doses.