Non-linear diffusion of cosmic rays escaping from supernova remnants – II. Hot ionized media. (arXiv:1903.03193v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nava_L/0/1/0/all/0/1">L. Nava</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Recchia_S/0/1/0/all/0/1">S. Recchia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gabici_S/0/1/0/all/0/1">S. Gabici</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marcowith_A/0/1/0/all/0/1">A. Marcowith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brahimi_L/0/1/0/all/0/1">L. Brahimi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ptuskin_V/0/1/0/all/0/1">V. Ptuskin</a>
We study the problem of the escape and transport of Cosmic-Rays (CR) from a
source embedded in a fully ionised, hot phase of the interstellar medium (HIM).
In particular, we model the CR escape and their propagation in the source
vicinity taking into account excitation of Alfv’enic turbulence by CR
streaming and mechanisms damping the self-excited turbulence itself. Our
estimates of escape radii and times result in large values (100 pc,
$2times10^5$ yr) for particle energies $lesssim20$ GeV and smaller values for
particles with increasing energies (35 pc and 14 kyr at 1 TeV). These escape
times and radii, when used as initial conditions for the CR propagation outside
the source, result in relevant suppression of the diffusion coefficient (by a
factor 5-10) on time-scales comparable with their (energy dependent) escape
time-scale. The damping mechanisms are fast enough that even on shorter time
scales the Alfv’enic turbulence is efficiently damped, and the ratio between
random and ordered component of the magnetic field is $delta B/B_0ll 1$,
justifying the use of quasi-linear theory. In spite of the suppressed diffusion
coefficient, and then the increased residence time in the vicinity (<200 pc) of
their source, the grammage accumulated by CRs after their escape is found to be
negligible (at all energies) as compared to the one accumulated while diffusing
in the whole Galaxy, due to the low density of the HIM.
We study the problem of the escape and transport of Cosmic-Rays (CR) from a
source embedded in a fully ionised, hot phase of the interstellar medium (HIM).
In particular, we model the CR escape and their propagation in the source
vicinity taking into account excitation of Alfv’enic turbulence by CR
streaming and mechanisms damping the self-excited turbulence itself. Our
estimates of escape radii and times result in large values (100 pc,
$2times10^5$ yr) for particle energies $lesssim20$ GeV and smaller values for
particles with increasing energies (35 pc and 14 kyr at 1 TeV). These escape
times and radii, when used as initial conditions for the CR propagation outside
the source, result in relevant suppression of the diffusion coefficient (by a
factor 5-10) on time-scales comparable with their (energy dependent) escape
time-scale. The damping mechanisms are fast enough that even on shorter time
scales the Alfv’enic turbulence is efficiently damped, and the ratio between
random and ordered component of the magnetic field is $delta B/B_0ll 1$,
justifying the use of quasi-linear theory. In spite of the suppressed diffusion
coefficient, and then the increased residence time in the vicinity (<200 pc) of
their source, the grammage accumulated by CRs after their escape is found to be
negligible (at all energies) as compared to the one accumulated while diffusing
in the whole Galaxy, due to the low density of the HIM.
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