Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Generation of proton aurora by magnetosonic waves.

ABSTRACT: Earth's proton aurora occurs over a broad MLT region and is produced by the precipitation of low-energy (2-10 keV) plasmasheet protons. Proton precipitation can alter chemical compositions of the atmosphere, linking solar activity with global climate variability. Previous studies proposed that electromagnetic ion cyclotron waves can resonate with protons, producing proton scattering precipitation. A long-outstanding question still remains whether there is another mechanism responsible for the proton aurora. Here, by performing satellite data analysis and diffusion equation calculations, we show that fast magnetosonic waves can produce trapped proton scattering that yields proton aurora. This provides a new insight into the mechanism of proton aurora. Furthermore, a ray-tracing study demonstrates that magnetosonic wave propagates over a broad MLT region, consistent with the global distribution of proton aurora.

SUBMITTER: Xiao F

PROVIDER: S-EPMC4046131 | biostudies-other | 2014

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Determining the mechanism of cusp proton aurora.

Project description:Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2-10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora.

| S-EPMC3622916 | biostudies-other

Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves.

Project description:The brightness of aurorae in Earth's polar region often beats with periods ranging from sub-second to a few tens of a second. Past observations showed that the beat of the aurora is composed of a superposition of two independent periodicities that co-exist hierarchically. However, the origin of such multiple time-scale beats in aurora remains poorly understood due to a lack of measurements with sufficiently high temporal resolution. By coordinating experiments using ultrafast auroral imagers deployed in the Arctic with the newly-launched magnetospheric satellite Arase, we succeeded in identifying an excellent agreement between the beats in aurorae and intensity modulations of natural electromagnetic waves in space called "chorus". In particular, sub-second scintillations of aurorae are precisely controlled by fine-scale chirping rhythms in chorus. The observation of this striking correlation demonstrates that resonant interaction between energetic electrons and chorus waves in magnetospheres orchestrates the complex behavior of aurora on Earth and other magnetized planets.

| S-EPMC7042315 | biostudies-literature

Remotely Controlled Proton Generation for Neuromodulation.

Project description:Understanding and modulating proton-mediated biochemical processes in living organisms have been impeded by the lack of tools to control local pH. Here, we design nanotransducers capable of converting noninvasive alternating magnetic fields (AMFs) into protons in physiological environments by combining magnetic nanoparticles (MNPs) with polymeric scaffolds. When exposed to AMFs, the heat dissipated by MNPs triggered a hydrolytic degradation of surrounding polyanhydride or polyester, releasing protons into the extracellular space. pH changes induced by these nanotransducers can be tuned by changing the polymer chemistry or AMF stimulation parameters. Remote magnetic control of local protons was shown to trigger acid-sensing ion channels and to evoke intracellular calcium influx in neurons. By offering a wireless modulation of local pH, our approach can accelerate the mechanistic investigation of the role of protons in biochemical signaling in the nervous system.

| S-EPMC8558523 | biostudies-literature

Environment-dependent generation of photoacoustic waves from plasmonic nanoparticles.

Project description:Nanoparticle-augmented photoacoustics is an emerging technique for molecular imaging. This study investigates the fundamental process of the photoacoustic signal generation by plasmonic nanoparticles suspended in a weakly absorbing fluid. The photoacoustic signal of gold nanospheres with varying silica shell thicknesses is shown to be dominated by the heat transfer between the nanoparticles and the surrounding environment.

| S-EPMC3498448 | biostudies-literature

Kinetic Generation of Whistler Waves in the Turbulent Magnetosheath.

Project description:The Earth's magnetosheath (MSH) is governed by numerous physical processes which shape the particle velocity distributions and contribute to the heating of the plasma. Among them are whistler waves which can interact with electrons. We investigate whistler waves detected in the quasi-parallel MSH by NASA's Magnetospheric Multiscale mission. We find that the whistler waves occur even in regions that are predicted stable to wave growth by electron temperature anisotropy. Whistlers are observed in ion-scale magnetic minima and are associated with electrons having butterfly-shaped pitch-angle distributions. We investigate in detail one example and, with the support of modeling by the linear numerical dispersion solver Waves in Homogeneous, Anisotropic, Multicomponent Plasmas, we demonstrate that the butterfly distribution is unstable to the observed whistler waves. We conclude that the observed waves are generated locally. The result emphasizes the importance of considering complete 3D particle distribution functions, and not only the temperature anisotropy, when studying plasma wave instabilities.

| S-EPMC9541185 | biostudies-literature

Proton-Enhanced Dielectric Properties of Polyoxometalates in Water under Radio-Frequency Electromagnetic Waves.

Project description:Electromagnetic waves, such as microwaves, have been used to enhance various chemical reactions over polyoxometalates. The dielectric properties of catalysts are among the relevant parameters facilitating catalytic reactions under electromagnetic radiation. This study describes the dielectric properties of polyoxometalate catalysts in aqueous and organic solutions to understand the mechanism of interactions between polyoxometalates and electromagnetic waves. Specific loss factors of polyoxometalates were observed at lower frequencies (<1 GHz) by the ionic conduction of the polyoxometalate solution. The evolution of ionic conduction depended strongly on cations rather than anions. Proton-type polyoxometalates exhibited significantly higher loss factors than other cations did. The activation energy for ionic conduction in protonated silicotungstic acid (H?SiW12O40) was significantly low in water (7.6?14.1 kJ/mol); therefore, the high loss factor of protonated polyoxometalates in water was attributed to the proton relay mechanism (i.e., Grotthuss mechanism). The results suggested that the proton relay mechanism at the radio-frequency band is critical for generating selective interactions of polyoxometalates with applied electromagnetic fields.

| S-EPMC6073116 | biostudies-literature

PROTON

Project description:Gut microbiota profile and plasma metabolome and lipidome in type 1 diabetes without and with stratification by albuminuria

| PRJEB46664 | ENA

Time reversed optical waves by arbitrary vector spatiotemporal field generation.

Project description:Lossless linear wave propagation is symmetric in time, a principle which can be used to create time reversed waves. Such waves are special "pre-scattered" spatiotemporal fields, which propagate through a complex medium as if observing a scattering process in reverse, entering the medium as a complicated spatiotemporal field and arriving after propagation as a desired target field, such as a spatiotemporal focus. Time reversed waves have previously been demonstrated for relatively low frequency phenomena such as acoustics, water waves and microwaves. Many attempts have been made to extend these techniques into optics. However, the much higher frequencies of optics make for very different requirements. A fully time reversed wave is a volumetric field with arbitrary amplitude, phase and polarisation at every point in space and time. The creation of such fields has not previously been possible in optics. We demonstrate time reversed optical waves with a device capable of independently controlling all of light's classical degrees of freedom simultaneously. Such a class of ultrafast wavefront shaper is capable of generating a sequence of arbitrary 2D spatial/polarisation wavefronts at a bandwidth limited rate of 4.4 THz. This ability to manipulate the full field of an optical beam could be used to control both linear and nonlinear optical phenomena.

| S-EPMC7669854 | biostudies-literature

Generation of electromagnetic waves with arbitrary orbital angular momentum modes.

Project description:Recently, much attention has been focused on beams carrying orbital angular momentum (OAM) for radio communication. Here we experimentally demonstrate a planar-spiral phase plate (planar-SPP) for generating arbitrary mixed OAM beams. This proposed planar-SPP uses the concept of transmit array antenna having a perforated substrate to control the outputting phase for generating beams carrying OAM with arbitrary modes. As demonstrations, three planar-SPPs with a single OAM mode and two mixed OAM modes around 94 GHz have been investigated with design and experiments in this paper, respectively. The typical experimental intensity and phase patterns show that the proposed method of generating OAM beams really works.

| S-EPMC4001093 | biostudies-other

Vortex Beam Generation by Spin-Orbit Interaction with Bloch Surface Waves.

Project description:Axis-symmetric grooves milled in metallic slabs have been demonstrated to promote the transfer of Orbital Angular Momentum (OAM) from far- to near-field and vice versa, thanks to spin-orbit coupling effects involving Surface Plasmons (SP). However, the high absorption losses and the polarization constraints, which are intrinsic in plasmonic structures, limit their effectiveness for applications in the visible spectrum, particularly if emitters located in close proximity to the metallic surface are concerned. Here, an alternative mechanism for vortex beam generation is presented, wherein a free-space radiation possessing OAM is obtained by diffraction of Bloch Surface Waves (BSWs) on a dielectric multilayer. A circularly polarized laser beam is tightly focused on the multilayer surface by means of an immersion optics, such that TE-polarized BSWs are launched radially from the focused spot. While propagating on the multilayer surface, BSWs exhibit a spiral-like wavefront due to the Spin-Orbit Interaction (SOI). A spiral grating surrounding the illumination area provides for the BSW diffraction out-of-plane and imparts an additional azimuthal geometric phase distribution defined by the topological charge of the spiral structure. At infinity, the constructive interference results into free-space beams with defined combinations of polarization and OAM satisfying the conservation of the Total Angular Momentum, based on the incident polarization handedness and the spiral grating topological charge. As an extension of this concept, chiral diffractive structures for BSWs can be used in combination with surface cavities hosting light sources therein.

| S-EPMC7901667 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data