scholarly journals Synchrotron emission from a nearby zone of Sgr A

2021 ◽  
Vol 503 (3) ◽  
pp. 3592-3595
Author(s):  
G Gogaberishvili ◽  
Z N Osmanov ◽  
S M Mahajan
Keyword(s):  
Synchrotron Radiation ◽  
Pitch Angle ◽  
Spectral Band ◽  
Synchrotron Emission ◽  
Linear Diffusion ◽  
X Ray ◽  
Cyclotron Instability ◽  
Angle Scattering ◽  
Sgr A

ABSTRACT Quasi-linear diffusion (QLD), driven by cyclotron instability, is proposed as a mechanism for the possible generation of synchrotron emission in the nearby zone of Sgr A*. For physically reasonable parameters, QLD, by causing non-zero pitch angle scattering, lets electrons with relativistic factors of the order of 108 emit synchrotron radiation in the hard X-ray spectral band ∼120 keV.

Information retrieval from X-ray small-angle scattering with polychromatic (`white') synchrotron radiation

1983 ◽  
Vol 16 (1) ◽  
pp. 42-46 ◽  
Author(s):  
O. Glatter ◽  
P. Laggner
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
Particle Shape ◽  
Structural Information ◽  
Small Angle Scattering ◽  
Radius Of Gyration ◽  
X Ray ◽  
Angle Scattering ◽  
Slit Length ◽  
Hinge Bending

The possibilities of obtaining structural information from X-ray small-angle scattering experiments with `white' polychromatic synchrotron radiation using line collimation are investigated by numerical simulation. Theoretical scattering curves of geometrical models were smeared with the appropriate wavelength distributions and slit-length functions, afflicted by statistical noise, and then evaluated by identical methods as normally used for experimental data, as described previously [program ITP; Glatter (1977). J. Appl. Cryst. 10, 415–421]. It is shown that even for a wavelength distribution of 50% half width, the information content is not limited to the parameters derived from the central part of the scattering curves, i.e. the radius of gyration and the zero-angle intensity, but also allows qualitative information on particle shape via the distance distribution function p(r). By a `hinge-bending model' consisting of two cylinders linked together at different angles it is demonstrated that changes in the radius of gyration amounting to less than 5% can be detected and quantified, and the qualitative changes in particle shape be reproduced.

Subgrid modelling of ion pitch-angle scattering for magnetosheath waves in a global hybrid-Vlasov simulation

2021 ◽  
Author(s):  
Maxime Dubart ◽  
Urs Ganse ◽  
Adnane Osmane ◽  
Andreas Johlander ◽  
Markus Battarbee ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Numerical Simulations ◽  
Spatial Resolution ◽  
Pitch Angle ◽  
Space Physics ◽  
Distribution Functions ◽  
Cyclotron Instability ◽  
Angle Scattering ◽  
Velocity Distribution Functions ◽  
Proton Cyclotron

<p>Numerical simulations are widely used in modern space physics and are an essential tool to understand or discover new phenomena which cannot be observed using spacecraft measurements. However, numerical simulations are limited by the space grid resolution of the system and the computational costs of having a high spatial resolution. Therefore, some physics may be unresolved in part of the system due to its low spatial resolution. We have previously identified, using Vlasiator, that the proton cyclotron instability is not resolved for grid cell sizes larger than four times the inertial length in the solar wind, for waves in the downstream of the quasi-perpendicular shock in the magnetosheath of a global hybrid-Vlasov simulation. This leads to unphysically high perpendicular temperature and a dominance of the mirror mode waves. In this study, we use high-resolution simulations to measure and quantify how the proton cyclotron instability diffuses and isotropizes the velocity distribution functions. We investigate the process of pitch-angle scattering during the development of the instability and propose a method for the sub-grid modelling of the diffusion process of the instability at low resolution. This allows us to model the isotropization of the velocity distribution functions and to reduce the temperature anisotropy in the plasma while saving computational resources.</p>

Electron pitch angle scattering and the impulsive phase microwave and hard X-ray emission from solar flares

1982 ◽  
Vol 257 ◽  
pp. 354 ◽  
Author(s):  
G. D. Holman ◽  
M. R. Kundu ◽  
K. Papadopoulos
Keyword(s):  
Solar Flares ◽  
Pitch Angle ◽  
Impulsive Phase ◽  
X Ray ◽  
Angle Scattering

scholarly journals EVIDENCE FOR X-RAY SYNCHROTRON EMISSION FROM SIMULTANEOUS MID-INFRARED TO X-RAY OBSERVATIONS OF A STRONG Sgr A* FLARE

2009 ◽  
Vol 698 (1) ◽  
pp. 676-692 ◽  
Author(s):  
K. Dodds-Eden ◽  
D. Porquet ◽  
G. Trap ◽  
E. Quataert ◽  
X. Haubois ◽  
...  
Keyword(s):  
Synchrotron Emission ◽  
Mid Infrared ◽  
X Ray ◽  
Sgr A

Microcrystallography with an X-ray waveguide

2000 ◽  
Vol 33 (5) ◽  
pp. 1231-1240 ◽  
Author(s):  
M. Müller ◽  
M. Burghammer ◽  
D. Flot ◽  
C. Riekel ◽  
C. Morawe ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
European Synchrotron Radiation Facility ◽  
Small Angle Scattering ◽  
Beam Size ◽  
X Ray ◽  
Multilayer Mirror ◽  
Angle Scattering ◽  
Polymeric Samples

A waveguide microdiffraction setup is described for an undulator beamline at the European Synchrotron Radiation Facility. The composite optics consists of a waveguide, which confines the beam vertically, and a horizontally focusing multilayer mirror. A beam size of about 0.1 × 3 µm (vertical × horizontal) at λ = 0.095 nm has been obtained. The sample stage comprises a three-axis gantry with micrometre precision and a three-axis piezo-scanner with about 0.1 µm repeatability. Diffraction experiments are demonstrated for selected inorganic and polymeric samples. Possibilities for scanning diffractometry and small-angle scattering experiments are discussed.

Soft X-Ray Small-Angle Scattering by Polystyrene Latexes Using Synchrotron Radiation

1978 ◽  
Vol 44 (4) ◽  
pp. 1314-1322 ◽  
Author(s):  
Katsuzo Wakabayashi ◽  
Akito Kakizaki ◽  
Yasuo Siota ◽  
Keiichi Namba ◽  
Kimio Kurita ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
Small Angle Scattering ◽  
X Ray ◽  
Angle Scattering

X-ray diffuser

2004 ◽  
Vol 37 (5) ◽  
pp. 841-842 ◽  
Author(s):  
Yoshiki Matsuura ◽  
Izumi Yoshizaki ◽  
Masahiko Tanaka
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
Small Angle Scattering ◽  
Beam Divergence ◽  
Amorphous Boron ◽  
Boron Powder ◽  
X Ray ◽  
Peak Finding ◽  
Angle Scattering

Amorphous boron powder was used as an X-ray diffuser, making the beam divergence of synchrotron radiation broader by simple insertion of the diffuser into the beam. The diffuser has been used successfully for the purpose of easy peak finding on a four-circle diffractometer. The diffuser effect is considered to be brought about by small-angle scattering from the boron powder.

scholarly journals TURBULENT PITCH-ANGLE SCATTERING AND DIFFUSIVE TRANSPORT OF HARD X-RAY-PRODUCING ELECTRONS IN FLARING CORONAL LOOPS

2013 ◽  
Vol 780 (2) ◽  
pp. 176 ◽  
Author(s):  
Eduard P. Kontar ◽  
Nicolas H. Bian ◽  
A. Gordon Emslie ◽  
Nicole Vilmer
Keyword(s):  
Pitch Angle ◽  
Coronal Loops ◽  
Diffusive Transport ◽  
X Ray ◽  
Angle Scattering
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