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Title: STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING

Abstract

The origin of hard X-ray (HXR) excess emission from clusters of galaxies is still an enigma, whose nature is debated. One of the possible mechanisms to produce this emission is the bremsstrahlung model. However, previous analytical and numerical calculations showed that in this case the intracluster plasma had to be overheated very fast because suprathermal electrons emitting the HXR excess lose their energy mainly by Coulomb losses, i.e., they heat the background plasma. It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by the background plasma. In other words, the Fermi acceleration is ineffective for particle acceleration. We revisited this problem and found that at some parameter of acceleration the rate of plasma heating is rather low and the acceleration tails of nonthermal particles can be generated and exist for a long time while the plasma temperature is almost constant. We showed also that for some regime of acceleration the plasma cools down instead of being heated up, even though external sources (in the form of external acceleration) supply energymore » to the system. The reason is that the acceleration withdraws effectively high-energy particles from the thermal pool (analog of Maxwell demon).« less

Authors:
;  [1];  [2]
  1. I. E. Tamm Theoretical Physics Division of P. N. Lebedev Institute, Leninskii pr 53, 119991 Moscow (Russian Federation)
  2. Institute of Astronomy, National Central University, JhongLi 320, Taiwan (China)
Publication Date:
OSTI Identifier:
22086394
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ASTROPHYSICS; BREMSSTRAHLUNG; COSMIC ELECTRONS; ELECTRON EMISSION; ELECTRON TEMPERATURE; GALAXY CLUSTERS; GAMMA ASTRONOMY; HARD X RADIATION; ION TEMPERATURE; PHOTON EMISSION; PLASMA; PLASMA HEATING; STOCHASTIC PROCESSES; X-RAY GALAXIES

Citation Formats

Chernyshov, D. O., Dogiel, V. A., and Ko, C. M., E-mail: cmko@astro.ncu.edu.tw. STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/113.
Chernyshov, D. O., Dogiel, V. A., & Ko, C. M., E-mail: cmko@astro.ncu.edu.tw. STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING. United States. doi:10.1088/0004-637X/759/2/113.
Chernyshov, D. O., Dogiel, V. A., and Ko, C. M., E-mail: cmko@astro.ncu.edu.tw. Sat . "STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING". United States. doi:10.1088/0004-637X/759/2/113.
@article{osti_22086394,
title = {STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING},
author = {Chernyshov, D. O. and Dogiel, V. A. and Ko, C. M., E-mail: cmko@astro.ncu.edu.tw},
abstractNote = {The origin of hard X-ray (HXR) excess emission from clusters of galaxies is still an enigma, whose nature is debated. One of the possible mechanisms to produce this emission is the bremsstrahlung model. However, previous analytical and numerical calculations showed that in this case the intracluster plasma had to be overheated very fast because suprathermal electrons emitting the HXR excess lose their energy mainly by Coulomb losses, i.e., they heat the background plasma. It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by the background plasma. In other words, the Fermi acceleration is ineffective for particle acceleration. We revisited this problem and found that at some parameter of acceleration the rate of plasma heating is rather low and the acceleration tails of nonthermal particles can be generated and exist for a long time while the plasma temperature is almost constant. We showed also that for some regime of acceleration the plasma cools down instead of being heated up, even though external sources (in the form of external acceleration) supply energy to the system. The reason is that the acceleration withdraws effectively high-energy particles from the thermal pool (analog of Maxwell demon).},
doi = {10.1088/0004-637X/759/2/113},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}