Article
Geosciences, Multidisciplinary
Delores Knipp, Liam Kilcommons, Marc Hairston, W. Robin Coley
Summary: Based on DMSP data, the study finds that the northern hemisphere receives more quasi-static Poynting flux than the southern hemisphere, partially due to more solar illumination and stronger field-aligned currents in the NH. There is stronger PF in the dusk region of the NH and in the mid-morning of the SH, while PF deposition near the cusp regions rivals and often exceeds that in the auroral zones.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
C. M. Liu, H. S. Fu, Y. Q. Yu, H. Y. Lu, W. L. Liu, Y. Xu, B. L. Giles, J. L. Burch
Summary: The study presents a detailed investigation of energy flux densities at two dipolarization fronts (DFs) using high-cadence data from MMS spacecraft, showing that electron enthalpy flux increases significantly during DF intervals, carrying the greatest energy, while ion enthalpy flux barely changes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
A. Brenner, T. I. Pulkkinen, Q. Al Shidi, G. Toth
Summary: This study presents new analysis methods for studying 3D MHD output data from the Space Weather Modeling Framework during a simulated storm event. The study reveals two energy pathways in Earth's magnetosphere, one external and one internal. The internal pathway, which has not been studied before, controls the energy content in the magnetosphere and the partitioning of energy between different regions.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Liam M. Kilcommons, Delores J. Knipp, Marc Hairston, W. Robin Coley
Summary: Poynting flux is an important measure of energy exchange between the magnetosphere and ionosphere. This study calculates earthward Poynting flux using data from DMSP spacecraft and validates the method by comparing flux measurements from different spacecraft. The study also obtains average spatial patterns of flux, magnetic perturbation, electric field, and ion drift velocity using an equal-area binning technique. The inclusion of full-field components significantly increases the strength of near-cusp flux and the integrated high-latitude flux by about 25%.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Multidisciplinary Sciences
J. W. R. Schroeder, G. G. Howes, C. A. Kletzing, F. Skiff, T. A. Carter, S. Vincena, S. Dorfman
Summary: Laboratory measurements have shown that under relevant conditions, Alfven waves can transfer energy to electrons, accelerating them to the energies required to produce auroras. Through experiments, theory, and simulations, a clear causal relationship between Alfven waves and accelerated electrons that directly cause auroras has been demonstrated.
NATURE COMMUNICATIONS
(2021)
Article
Astronomy & Astrophysics
Dominika L. Krol, Lukasz Stawarz, Mitchell C. Begelman, Jose-Maria Marti, Manel Perucho, Bohdan A. Petrenko
Summary: This article discusses a simple analytical model for relativistic jets at larger distances from their launching sites. It is found that these outflows tend to be particle dominated rather than electromagnetic energy dominated when the jet plasma is in magnetohydrostatic equilibrium. The dominance of magnetic pressure over particle pressure is still possible for certain ranges of the jet radius, which is relevant for particle acceleration and high-energy emission in such systems.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Ziyi Yang, Binzheng Zhang, William Lotko, Kareem A. Sorathia, Kevin Pham, Xiaoli Luan, Xiankang Dou, Jiuhou Lei
Summary: Geomagnetic activity in Earth's outer magnetosphere produces intense Alfven waves carrying electromagnetic power towards Earth, with the greatest intensity observed in the magnetotail. Global magnetohydrodynamic simulations reveal that the distribution of these power fluxes is determined by the formation of Alfven conductance channels.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
D. D. Billett, K. A. McWilliams, I. P. Pakhotin, J. K. Burchill, D. J. Knudsen, C. J. Martin
Summary: Underestimation of energy transfer between the magnetosphere and ionosphere, known as Poynting flux, is a persistent problem in space weather studies. By examining small-scale electric field fluctuations, this study found that increasing the observed scale leads to a decrease in Poynting flux, with upward Poynting flux decreasing significantly faster. Additionally, a preference for increased Poynting flux in the northern hemisphere was observed, and its dependence on scale size and interplanetary magnetic field was analyzed.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Tian, C. A. Colpitts, J. R. Wygant, C. A. Cattell, C. P. Ferradas, A. B. Igl, B. A. Larsen, G. D. Reeves, E. F. Donovan
Summary: Geomagnetic substorms are significant energy transfer events, however, the complex interplay among various phenomena is not fully understood. Observations in 2013 revealed a temporal and spatial correlation between auroral activities and earthward Alfvenic Poynting flux, suggesting a direct link between them.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
S. Tian, L. R. Lyons, Y. Nishimura, J. R. Wygant, R. L. Lysak, C. P. Ferradas, X. An, A. B. Igl, G. D. Reeves, B. A. Larsen, D. Ma
Summary: Auroral beads are spatially wavy forms seen before auroral substorms, and their electron acceleration mechanism has been studied. Recent observations found that the presence of Alfvén waves and kinetic Alfvén waves (KAWs) are closely related to the generation of auroral beads. These waves accelerate electrons and contribute to the formation of the beads.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Optics
Yanxiang Zhang, Zijing Zhang, Qingfeng Wang, Yuan Zhao
Summary: Researchers have achieved high-accuracy transverse translation velocimetry by exploiting the dual-point transverse Doppler effect of customized orbital-angular-momentum light fields. They demonstrated for the first time that dual-point transverse Doppler shifts can be generated and detected in a single velocimetry setup, enabling the determination of arbitrary transverse translation velocity. Additionally, they improved velocimetry accuracy by increasing the sampling duration.
Article
Astronomy & Astrophysics
D. D. Billett, G. W. Perry, L. B. N. Clausen, W. E. Archer, K. A. McWilliams, S. Haaland, J. P. Reistad, J. K. Burchill, M. R. Patrick, B. K. Humberset, B. J. Anderson
Summary: This study examines the relationship between large thermospheric neutral density enhancements in the cusp region and magnetospheric energy input, showing fine-scale Poynting fluxes associated with density perturbations. However, the lack of correlation between mesoscale height-integrated Poynting fluxes and cusp neutral mass density enhancement suggests possible other processes accounting for the discrepancy.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Optics
Yan Wu, Xiaobo Hu, Yuhua Li, Ruipin Chen
Summary: Using the Richards-Wolf diffraction integral, the longitudinal energy evolution of fractional order vector vortex (FOVV) beams on the focal plane was studied. The existence of backflow energy was revealed when the binary topological charges satisfied specific conditions. Component circularly polarized vortex beams played significant roles in generating reverse energy flux. The longitudinal energy on the focal plane exhibited axial symmetry for FOVV beams with integer sums and differences of binary topological charges, but was disrupted when the sums or differences were not integers.
Article
Nanoscience & Nanotechnology
Ayan Majumder, Dakotah Thompson, Rohith Mittapally, Pramod Reddy, Edgar Meyhofer
Summary: Control of nanoscale thermal transport is crucial for various applications. Previous studies have suggested that enhanced heat transfer in planar membranes with nanoscale thickness is due to directional and spatially confined in-plane heat transfer. However, experimental evidence for this confinement is lacking. This study directly quantifies the spatial extent of heat transfer and provides detailed explanations for the observations, potentially leading to new approaches for active control of nanoscale heat flow.
Article
Geochemistry & Geophysics
D. Mashao, M. Kosch, M. Fullekrug
Summary: We provide calibrated estimates of photon flux, lightning peak Poynting flux, and Joule heating associated with the brightest region of sprites observed in the mesosphere over South Africa. The study reveals variations in the lightning-driven background electric field and its influence on carrot sprites and column sprites formation processes. The estimates of lightning peak Poynting flux and Joule heating shed light on the average values in the brightest region of sprites, and it is found that they decrease with increasing atmospheric altitude. The time delay between column sprites and their parent lightning strokes is shorter compared to carrot sprites.
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
(2023)