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Small-amplitude Compressible Magnetohydrodynamic Turbulence Modulated by Collisionless Damping in Earth's Magnetosheath: Observation Matches Theory
Liu, Terry Z.; Zhao, Siqi; Yan, Huirong +2 more
Plasma turbulence is a ubiquitous dynamical process that transfers energy across many spatial and temporal scales and affects energetic particle transport. Recent advances in the understanding of compressible magnetohydrodynamic (MHD) turbulence demonstrate the important role of damping in shaping energy distributions on small scales, yet its obse…
What is the Reynolds Number of the Solar Wind?
Wrench, Daniel; Parashar, Tulasi N.; Oughton, Sean +2 more
The Reynolds number, Re, is an important quantity for describing a turbulent flow. It tells us about the bandwidth over which energy can cascade from large scales to smaller ones, prior to the onset of dissipation. However, calculating it for nearly collisionless plasmas like the solar wind is challenging. Previous studies have used formulations o…
Upstream Plasma Waves and Downstream Magnetic Reconnection at a Reforming Quasi-parallel Shock
Yang, Zhongwei; Lu, Quanming; Gao, Xinliang +4 more
With the help of a two-dimensional particle-in-cell simulation model, we investigate the long-time evolution (near $100{{\rm{\Omega }}}_{i0}^{-1}$ , where Ω i0 is the ion gyrofrequency in the upstream) of a quasi-parallel shock. Some of the upstream ions are reflected by the shock front, and their interactions with the incident ions exc…
Oblique Electrostatic Solitary and Supersolitary Waves in Earth's Magnetosheath
Singh, Kuldeep; Varghese, Steffy Sara; Saini, Nareshpal Singh +1 more
Nonlinear electrostatic solitary waves (ESWs) are routinely detected at various regions of Earth's magnetosphere using the Wideband Data plasma wave receivers mounted on board the Cluster satellite(s). This mission has facilitated the observation and analysis of ESW characteristics, such as amplitude and temporal duration within the magnetosheath,…
Local Transition of Electron Pitch Angle Distribution within Flux Pileup Region behind Dipolarization Front
Cao, J. B.; Liu, Y. Y.; Liu, C. M. +2 more
Dipolarization fronts (DFs), earthward-propagating magnetic transients with a strong magnetic field, are important regions favorable for energetic electron acceleration in the magnetotail. The DF-driven electron acceleration usually generates coherent pitch angle distributions (PADs) inside flux pileup regions (FPRs), i.e., strong magnetic field r…
Radial Distribution of Electron Quasi-thermal Noise in the Inner Heliosphere
Chen, Ling; Li, Yi-Lun; Wu, De-Jin
The electron population in the solar wind plasma can be described with three different components: a core, a halo, and a magnetic field aligned strahl. The electron quasi-thermal noise (QTN) is investigated by using an electron population model consisting of a core with a Maxwellian distribution and a halo with a kappa distribution, based on the e…
An Anisotropic Density Turbulence Model from the Sun to 1 au Derived from Radio Observations
Kontar, Eduard P.; Chen, Xingyao; Chrysaphi, Nicolina +5 more
Solar radio bursts are strongly affected by radio-wave scattering on density inhomogeneities, changing their observed time characteristics, sizes, and positions. The same turbulence causes angular broadening and scintillation of galactic and extragalactic compact radio sources observed through the solar atmosphere. Using large-scale simulations of…
Multipoint Turbulence Analysis with HelioSwarm
Servidio, Sergio; Pecora, Francesco; Primavera, Leonardo +3 more
Exploration of plasma dynamics in space, including turbulence, is entering a new era of multisatellite constellation measurements that will determine fundamental properties with unprecedented precision. Familiar but imprecise approximations will need to be abandoned and replaced with more-advanced approaches. We present a preparatory study of the …
Kinetic Alfvén Waves Excited by Multiple Free Energy Sources in the Magnetotail
Lakhina, G. S.; Singh, S. V.; Barik, K. C.
The generation of kinetic Alfvén waves (KAWs) is investigated through a three-component theoretical model incorporating ion beam and velocity shear as the sources of free energy in a non-Maxwellian κ-distributed plasmas. The model considers Maxwellian distributed background ions, drifting-Maxwellian beam ions, and κ-electrons as its constituent sp…
Non-universality of the Turbulent Spectra at Sub-ion Scales in the Solar Wind: Dispersive Effects versus the Doppler Shift
Sahraoui, Fouad; Huang, Shiyong
Large surveys of the power spectral density of the magnetic fluctuations in the solar wind have reported different slope distributions at MHD, sub-ion and sub-electron scales: the smaller the scale, the broader the distribution. Here, we review briefly some of the most relevant explanations of the broadening of the slopes at sub-ion scales. Then, …