scholarly journals Weak Alfvénic turbulence in relativistic plasmas. Part 1. Dynamical equations and basic dynamics of interacting resonant triads

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
J.M. TenBarge ◽  
B. Ripperda ◽  
A. Chernoglazov ◽  
A. Bhattacharjee ◽  
J.F. Mahlmann ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Building Blocks ◽  
High Energy ◽  
Alfven Wave ◽  
Dynamical Equations ◽  
Important Distinction ◽  
Relativistic Limit ◽  
Oblique Propagation ◽  
Field Lines ◽  
Relativistic Magnetohydrodynamics

Alfvén wave collisions are the primary building blocks of the non-relativistic turbulence that permeates the heliosphere and low- to moderate-energy astrophysical systems. However, many astrophysical systems such as gamma-ray bursts, pulsar and magnetar magnetospheres and active galactic nuclei have relativistic flows or energy densities. To better understand these high-energy systems, we derive reduced relativistic magnetohydrodynamics equations and employ them to examine weak Alfvénic turbulence, dominated by three-wave interactions, in reduced relativistic magnetohydrodynamics, including the force-free, infinitely magnetized limit. We compare both numerical and analytical solutions to demonstrate that many of the findings from non-relativistic weak turbulence are retained in relativistic systems. But, an important distinction in the relativistic limit is the inapplicability of a formally incompressible limit, i.e. there exists finite coupling to the compressible fast mode regardless of the strength of the magnetic field. Since fast modes can propagate across field lines, this mechanism provides a route for energy to escape strongly magnetized systems, e.g. magnetar magnetospheres. However, we find that the fast-Alfvén coupling is diminished in the limit of oblique propagation.

scholarly journals Magnetic fractures or reconnection of type II

2010 ◽  
Vol 6 (S274) ◽  
pp. 56-61
Author(s):  
Gerhard Haerendel
Keyword(s):  
Particle Production ◽  
Gamma Ray ◽  
Magnetic Energy ◽  
High Energy ◽  
Compact Objects ◽  
High Energy Particle ◽  
Shear Stresses ◽  
Low Density ◽  
Field Lines ◽  
Auroral Arcs

AbstractThe importance of reconnection in astrophysics has been widely recognized. It is instrumental in storing and releasing magnetic energy, the latter often in a dramatic fashion. A closely related process, playing in very low beta plasmas, is much less known. It is behind the acceleration of auroral particles in the low-density environment several 1000 km above the Earth. It involves the appearance of field-parallel voltages in presence of intense field-aligned currents. The underlying physical process is the release of magnetic shear stresses and conversion of the liberated magnetic energy into kinetic energy of the particles creating auroral arcs. In this process, field lines disconnect from the field anchored in the ionosphere and reconnect to other field lines. Because of the stiffness of the magnetic field, the process resembles mechanical fractures. It is typically active in the low-density magnetosphere of planets. However, it can also lead to significant energy conversion with high-energy particle production and subsequent gamma ray emissions in stellar magnetic fields, in particular of compact objects.

HIGH-ENERGY EMISSION FROM PULSAR MAGNETOSPHERES

2006 ◽  
Vol 21 (17) ◽  
pp. 1319-1337 ◽  
Author(s):  
KOUICHI HIROTANI
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Potential Drop ◽  
High Energy ◽  
Particle Accelerators ◽  
Two Dimensional ◽  
Essential Information ◽  
Field Lines ◽  
Gap Models ◽  
Star Surface

A synthesis of the present knowledge on gamma-ray emission from the magnetosphere of a rapidly rotating neutron star is presented, focusing on the electrodynamics of particle accelerators. The combined curvature, synchrotron, and inverse-Compton emission from ultra-relativistic positrons and electrons, which are created by two-photon and/or one-photon pair creation processes, or emitted from the neutron-star surface, provide us with essential information on the properties of the accelerator — electric potential drop along the magnetic field lines. A new accelerator model, which is a mixture of traditional inner gap and outer gap models, is also proposed, by solving the Poisson equation for the electrostatic potential together with the Boltzmann equations for particles and gamma-rays in the two-dimensional configuration and two-dimensional momentum spaces.

scholarly journals The synchrotron mechanism and the high energy flare from PKS 1510-089

2021 ◽  
pp. 417-424
Author(s):  
Z. N. Osmanov
Keyword(s):  
Gamma Ray ◽  
Reaction Force ◽  
High Energy ◽  
Physical Parameters ◽  
Synchrotron Emission ◽  
Linear Diffusion ◽  
Wide Range ◽  
Energy Domain ◽  
Field Lines ◽  
Major Factors

In order to understand the role of the synchrotron emission in the high energy gamma-ray flares from PKS 1510-089, we study generation of the synchrotron emission by means of the feedback of cyclotron waves on the particle distribution via the diffusion process. The cyclotron resonance causes the diffusion of particles along and across the magnetic field lines. This process is described by the quasi-linear diffusion (QLD) that leads to the increase of pitch angles and generation of the synchrotron emission. We study the kinetic equation which defines the distribution of emitting particles. The redistribution is conditioned by two major factors, QLD and the dissipation process, that is caused by synchrotron reaction force. The QLD increases pitch angles, whereas the synchrotron force resists this process. The balance between these two forces guarantees the maintenance of the pitch angles and the corresponding synchrotron emission process. The model is analyzed for a wide range of physical parameters and it is shown that the mechanism of QLD provides the generation of high energy (HE) emission in the GeV energy domain. According to the model the lower energy, associated with the cyclotron modes, provokes the synchrotron radiation in the higher energy band.

scholarly journals Constraining spectral models of a terrestrial gamma-ray flash from a terrestrial electron beam observation by the Atmosphere-Space Interactions Monitor

2021 ◽  
Author(s):  
David Sarria ◽  
Nikolai Østgaard ◽  
Pavlo Kochkin ◽  
Nikolai Lehtinen ◽  
Andrew Mezentsev ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Spectrum ◽  
Gamma Ray ◽  
Space Station ◽  
High Energy ◽  
Source Spectrum ◽  
Relativistic Electrons ◽  
Electrons And Positrons ◽  
Spectral Models ◽  
Field Lines

<p>Terrestrial Gamma-ray Flashes (TGFs) are short flashes of high energy photons, produced by thunderstorms. When interacting with the atmosphere, they produce relativistic electrons and positrons, and a part gets bounded to geomagnetic field lines and travels large distances in space. This phenomenon is called a Terrestrial Electron Beam (TEB). The Atmosphere-Space Interactions Monitor (ASIM) mounted on-board the International Space Station detected a new TEB event on March 24, 2019, originating from a tropical cyclone, Johanina. Using ASIM's low energy detector, the TEB energy spectrum is resolved down to 50 keV. We provide a new method to contrain the TGF source spectrum based on the detected TEB spectrum. Applied to this event, it shows that only fully developed RREA spectrums are compatible with the observation. More specifically, assuming a TGF spectrum proportional to 1/E exp(-E/ε), the compatible models have ε ≥ 6.5 MeV. We could not exclude models with ε of 8 and 10 MeV. This is the first time the source energy spectrum of a TGF is contrained based on the detection of the associated TEB.</p>

FEATURES OF MAGNETIC STRUCTURE OF SUNSPOTS GROUPS AT DEVELOPMENT OF SUSTAINED FLUXES HIGH ENERGY GAMMA RAY

2020 ◽  
Vol 3 (331) ◽  
pp. 66-72
Author(s):  
Gennady Sergeevich, Minasyants ◽  
◽  
Tamara Mihailovna, Minasyants ◽  
Vladimir Mihailovich, Tomozov ◽  
◽  
...  
Keyword(s):  
Magnetic Structure ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Energy Gamma

scholarly journals UVscope and its application aboard the ASTRI-Horn telescope

2021 ◽  
Author(s):  
Maria Concetta Maccarone ◽  
Giovanni La Rosa ◽  
Osvaldo Catalano ◽  
Salvo Giarrusso ◽  
Alberto Segreto ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Single Photon ◽  
Photon Counting ◽  
Light Flux ◽  
Cosmic Ray ◽  
High Energy ◽  
Wide Field ◽  
High Energy Astrophysics ◽  
Single Photon Counting ◽  
Photon Counting Mode

AbstractUVscope is an instrument, based on a multi-pixel photon detector, developed to support experimental activities for high-energy astrophysics and cosmic ray research. The instrument, working in single photon counting mode, is designed to directly measure light flux in the wavelengths range 300-650 nm. The instrument can be used in a wide field of applications where the knowledge of the nocturnal environmental luminosity is required. Currently, one UVscope instrument is allocated onto the external structure of the ASTRI-Horn Cherenkov telescope devoted to the gamma-ray astronomy at very high energies. Being co-aligned with the ASTRI-Horn camera axis, UVscope can measure the diffuse emission of the night sky background simultaneously with the ASTRI-Horn camera, without any interference with the main telescope data taking procedures. UVscope is properly calibrated and it is used as an independent reference instrument for test and diagnostic of the novel ASTRI-Horn telescope.

scholarly journals Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Y. Miyoshi ◽  
K. Hosokawa ◽  
S. Kurita ◽  
S.-I. Oyama ◽  
Y. Ogawa ◽  
...  
Keyword(s):  
High Energy ◽  
Daily Basis ◽  
Maximum Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Mesospheric Ozone ◽  
Field Lines ◽  
Eiscat Radar

AbstractPulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.

scholarly journals Gamma-Ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 36
Author(s):  
Yoshiyuki Inoue ◽  
Dmitry Khangulyan ◽  
Akihiro Doi
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Thermal Activity ◽  
X Ray ◽  
Cascade Models ◽  
Coronal Activity ◽  
Ngc 1068 ◽  
High Energy Particles

To explain the X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts have established the existence of weak non-thermal coronal activity. In addition, the IceCube collaboration reported NGC 1068, a nearby Seyfert, as the hottest spot in their 10 yr survey. These pieces of evidence are enough to investigate the non-thermal perspective of AGN coronae in depth again. This article summarizes our current observational understanding of AGN coronae and describes how AGN coronae generate high-energy particles. We also provide ways to test the AGN corona model with radio, X-ray, MeV gamma ray, and high-energy neutrino observations.

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