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.

scholarly journals High-energy astrophysics and the search for sources of gravitational waves

2018 ◽  
Vol 376 (2120) ◽  
pp. 20170294 ◽  
Author(s):  
P. T. O'Brien ◽  
P. Evans
Keyword(s):  
Gravitational Wave ◽  
Short Duration ◽  
Gamma Ray ◽  
New Technology ◽  
High Energy ◽  
Compact Objects ◽  
Wide Field ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Binary Mergers

The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources—gamma-ray bursts (GRBs)—have long been considered as very likely sources of GWs, particularly from short-duration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star–black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for high-energy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new space missions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’.

scholarly journals High-Energy Multimessenger Transient Astrophysics

2019 ◽  
Vol 69 (1) ◽  
pp. 477-506 ◽  
Author(s):  
Kohta Murase ◽  
Imre Bartos
Keyword(s):  
Time Domain ◽  
Particle Production ◽  
High Energy ◽  
High Energy Particle ◽  
Energy Particle ◽  
Transient Phenomena ◽  
New Era ◽  
Astrophysical Objects ◽  
High Energy Emission

The recent discoveries of high-energy cosmic neutrinos and gravitational waves from astrophysical objects have led to a new era of multimessenger astrophysics. In particular, electromagnetic follow-up observations triggered by these cosmic signals have proved to be highly successful and have brought about new opportunities in time-domain astronomy. We review high-energy particle production in various classes of astrophysical transient phenomena related to black holes and neutron stars, and discuss how high-energy emission can be used to reveal the underlying physics of neutrino and gravitational-wave sources.

scholarly journals Energetic Particles in a Flare Loop: Spectra and Radiation Signatures

1990 ◽  
Vol 142 ◽  
pp. 421-427
Author(s):  
P. A. Bespalov ◽  
V. V. Zaitsev ◽  
A. V. Stepanov
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Propagation Model ◽  
Source Spectrum ◽  
High Energy Particle ◽  
Particle Interactions ◽  
Flare Loop ◽  
Energetic Ions ◽  
Particle Spectra ◽  
One Step

It has been shown that high energy particle spectra, particle dynamics, and radiation in a flare loop are determined by wave-particle interactions. The electron-whistler interaction occurs under conditions of strong pitch angle diffusion that makes the particle distribution function isotropic. The flare loop electrons retain information about the particle source spectrum. The interaction of energetic ions with Alfven waves is characterized by strong, moderate, and weak diffusion. The time delays in hard X-ray and gamma-ray emission during one-step acceleration processes might be understood in terms of a trap-plus-turbulent propagation model. The density of precipitating particles is less than or equal to the trapping one. Radiation signatures of flare loop electrons are discussed.

scholarly journals Electromagnetic transients and gravitational waves from white dwarf disruptions by stellar black holes in triple systems

2020 ◽  
Vol 495 (1) ◽  
pp. 1061-1072
Author(s):  
Giacomo Fragione ◽  
Brian D Metzger ◽  
Rosalba Perna ◽  
Nathan W C Leigh ◽  
Bence Kocsis
Keyword(s):  
White Dwarf ◽  
Gamma Ray ◽  
High Energy ◽  
Stellar Mass ◽  
Compact Objects ◽  
Electromagnetic Transients ◽  
Tidal Disruption ◽  
Single Star ◽  
Triple Systems ◽  
Nearby Galaxies

ABSTRACT Mergers of binaries comprising compact objects can give rise to explosive transient events, heralding the birth of exotic objects that cannot be formed through single-star evolution. Using a large number of direct N-body simulations, we explore the possibility that a white dwarf (WD) is dynamically driven to tidal disruption by a stellar-mass black hole (BH) as a consequence of the joint effects of gravitational wave (GW) emission and Lidov–Kozai oscillations imposed by the tidal field of an outer tertiary companion orbiting the inner BH–WD binary. We explore the sensitivity of our results to the distributions of natal kick velocities imparted to the BH and WD upon formation, adiabatic mass loss, semimajor axes and eccentricities of the triples, and stellar-mass ratios. We find rates of WD–tidal disruption events (TDEs) in the range 1.2 × 10−3 − 1.4 Gpc−3 yr−1 for z ≤ 0.1, rarer than stellar TDEs in triples by a factor of ∼3–30. The uncertainty in the TDE rates may be greatly reduced in the future using GW observations of Galactic binaries and triples with LISA. WD–TDEs may give rise to high-energy X-ray or gamma-ray transients of duration similar to long gamma-ray bursts but lacking the signatures of a core-collapse supernova, while being accompanied by a supernova-like optical transient that lasts for only days. WD–BH and WD–NS binaries will also emit GWs in the LISA band before the TDE. The discovery and identification of triple-induced WD–TDE events by future time domain surveys and/or GWs could enable the study of the demographics of BHs in nearby galaxies.

Ion Heating and High-Energy-Particle Production by Ion-Cyclotron Heating in the Large Helical Device

2000 ◽  
Vol 85 (21) ◽  
pp. 4530-4533 ◽  
Author(s):  
T. Mutoh ◽  
R. Kumazawa ◽  
T. Seki ◽  
T. Watari ◽  
K. Saito ◽  
...  
Keyword(s):  
Particle Production ◽  
High Energy ◽  
High Energy Particle ◽  
Energy Particle ◽  
Ion Heating ◽  
Ion Cyclotron

Future prospects for y-ray astronomy

1981 ◽  
Vol 301 (1462) ◽  
pp. 693-701 ◽  
Keyword(s):  
Gamma Ray ◽  
Dynamic Pressure ◽  
High Energy ◽  
Compact Objects ◽  
Pressure Effects ◽  
Very High Energy ◽  
Order Of Magnitude ◽  
High Energy Particles ◽  
Nuclear Processes ◽  
The Universe

As y-ray astronomy moves from the discovery to the exploratory phase, the promise of y-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the y-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the Solar System, the structure of our Galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the Universe. The y-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the y-ray burst network, Solar Polar, and very high energy y-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.

Astrophysics and Particle Physics in Space with the Alpha Magnetic Spectrometer

2003 ◽  
Vol 18 (28) ◽  
pp. 1951-1966 ◽  
Author(s):  
Giovanni Lamanna
Keyword(s):  
Particle Physics ◽  
Gamma Ray ◽  
Space Shuttle ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Magnetic Spectrometer ◽  
High Energy Particle ◽  
Physics Experiment ◽  
Alpha Magnetic Spectrometer

The Alpha Magnetic Spectrometer (AMS) is a high energy particle physics experiment in space scheduled to be installed on the International Space Station (ISS) by 2006 for a three-year mission. After a precursor flight of a prototype detector on board of the NASA Space Shuttle in June 1998, the construction of the detector in its final configuration is started and it will be completed by 2004. The purpose of this experiment is to provide a high statistics measurement of charged particles and nuclei in rigidity range 0.5 GV to few TV and to explore the high-energy (> 1 GeV ) gamma-ray sky. In this paper we describe the detector layout and present an overview of the main scientific goals both in the domain of astrophysics: cosmic-ray origin, age and propagation and the exploration of the most energetic gamma-ray sources; and in the domain of astroparticle: the anti-matter and the dark matter searches.

Ion cyclotron range of frequencies heating and high-energy particle production in the Large Helical Device

2003 ◽  
Vol 43 (8) ◽  
pp. 738-743 ◽  
Author(s):  
T Mutoh ◽  
R Kumazawa ◽  
T Seki ◽  
K Saito ◽  
T Watari ◽  
...  
Keyword(s):  
Particle Production ◽  
High Energy ◽  
High Energy Particle ◽  
Energy Particle ◽  
Ion Cyclotron

scholarly journals Physics of Gamma-Ray Bursts Prompt Emission

2015 ◽  
Vol 2015 ◽  
pp. 1-37 ◽  
Author(s):  
Asaf Pe’er
Keyword(s):  
Gamma Ray ◽  
Magnetic Energy ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Theoretical Research ◽  
Theoretical Interpretation ◽  
Time Resolved ◽  
Physical Conditions ◽  
Major Development ◽  
Prompt Emission

In recent years, our understanding of gamma-ray bursts (GRB) prompt emission has been revolutionized, due to a combination of new instruments, new analysis methods, and novel ideas. In this review, I describe the most recent observational results and current theoretical interpretation. Observationally, a major development is the rise of time resolved spectral analysis. These led to (I) identification of a distinguished high energy component, with GeV photons often seen at a delay and (II) firm evidence for the existence of a photospheric (thermal) component in a large number of bursts. These results triggered many theoretical efforts aimed at understanding the physical conditions in the inner jet regions. I highlight some areas of active theoretical research. These include (I) understanding the role played by magnetic fields in shaping the dynamics of GRB outflow and spectra; (II) understanding the microphysics of kinetic and magnetic energy transfer, namely, accelerating particle to high energies in both shock waves and magnetic reconnection layers; (III) understanding how subphotospheric energy dissipation broadens the “Planck” spectrum; and (IV) geometrical light aberration effects. I highlight some of these efforts and point towards gaps that still exist in our knowledge as well as promising directions for the future.

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