An Analytic Approximation for Plane‐parallel Compton Scattering near Accretion Disks

1999 ◽  
Vol 527 (1) ◽  
pp. 254-261
Author(s):  
Robert V. Wagoner ◽  
Alexander S. Silbergleit
Keyword(s):  
Compton Scattering ◽  
Accretion Disks ◽  
Analytic Approximation ◽  
Plane Parallel

scholarly journals Physics of Magnetized Accretion Disks in AGN

1994 ◽  
Vol 159 ◽  
pp. 480-481
Author(s):  
George Field ◽  
Robert Rogers
Keyword(s):  
Magnetic Field ◽  
Compton Scattering ◽  
Accretion Disks ◽  
Radiation Pressure ◽  
Synchrotron Emission ◽  
Inverse Compton Scattering ◽  
Nonthermal Radiation ◽  
Field Parallel ◽  
Inverse Compton

Field and Rogers (1993) proposed that the accretion disks in moderate - L AGN (≲ 1044 erg sec−1) are dominated by magnetic stress rather than gas or radiation pressure. A magnetic field parallel to the disk forms loops above and below it where reconnection accelerates electrons to relativistic energies. The nonthermal radiation observed is the synchrotron emission and inverse-Compton scattering by these electrons.

scholarly journals The softening of radiation by multiple Compton scattering

1948 ◽  
Vol 192 (1031) ◽  
pp. 508-518 ◽  
Keyword(s):  
Compton Scattering ◽  
High Probability ◽  
Wave Length ◽  
Free Electrons ◽  
Plane Parallel ◽  
Multiple Compton Scattering

The problem of the softening of radiation by multiple Compton scattering in an atmosphere of free electrons is considered. An idealized problem in plane-parallel atmospheres is formulated and the appropriate equation of transfer is approximately solved. The modified distributions with wave-length of the radiation emergent after transmission through various optical thicknesses of an incident monochromatic flux of radiation are tabulated. The calculations show that there is a relatively high probability for quite large shifts after transmission through optical thicknesses of order even unity.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

Accretion Discs in AGN, Viscosity and Structure of Accretion Disks

2001 ◽  
Vol 1 ◽  
pp. 53-61
Author(s):  
J.-M. Hure ◽  
D. Richard
Keyword(s):  
Accretion Disks ◽  
Accretion Discs

ELECTRON CORRELATION IN METALS EVIDENCED BY COMPTON SCATTERING

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-851-C9-854 ◽  
Author(s):  
A. ISSOLAH ◽  
j. CHOMILIER ◽  
Y. GARREAU ◽  
G. LOUPIAS
Keyword(s):  
Compton Scattering ◽  
Electron Correlation
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