From 695cb0272a2d6ea22e2d8988fdf723c1b944072f Mon Sep 17 00:00:00 2001 From: Aaron LI Date: Sun, 31 Dec 2017 16:36:56 +0800 Subject: clusters/halo: Rework the turbulence acceleration timescale calculation The new method adopted to determine the turbulence acceleration timescale follows [miniati2015] and [pinzke2017], in which the merger-induced turbulence cascades into small scales (and thus accelerate electrons) through the TTD (transit-time damping) mechanism by scattering mainly with the relativistic particles (cosmic-ray protons and electrons). --- fg21sim/configs/20-extragalactic.conf.spec | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'fg21sim/configs') diff --git a/fg21sim/configs/20-extragalactic.conf.spec b/fg21sim/configs/20-extragalactic.conf.spec index 52f66da..2924cf6 100644 --- a/fg21sim/configs/20-extragalactic.conf.spec +++ b/fg21sim/configs/20-extragalactic.conf.spec @@ -167,13 +167,25 @@ # used to determine the radio halo size. f_lturb = float(default=0.33, min=0.1, max=1.0) - # Ratio of the total energy injected into cosmic-ray electrons during - # the cluster life to its total thermal energy. + # An efficiency factor describing the effectiveness of plasma + # instabilities (e.g., due to spatial or temporal intermittency). + zeta_ins = float(default=0.1, min=0.1, max=1.0) + # The fraction of merger energy transferred into the turbulence. eta_turb = float(default=0.1, min=0.1, max=0.5) + # The fraction of the thermal energy injected into the cosmic-ray + # electrons during the cluster life time. eta_e = float(default=0.001, min=0.001, max=0.1) + # The ratio of cosmic ray (including protons and electrons) energy + # density (i.e., pressure) to the thermal energy density. + # NOTE: Fermi-LAT has placed an upper limit of ~1.25%-1.4% + # (Ackermann et al. 2014, ApJ, 787, 18) + # NOTE: The energy ratio of cosmic-ray electrons to protons K_ep ~0.01 + # for our Galaxy (Pinzke et al. 2017, MNRAS, 465, 4800) + x_cr = float(default=0.01, min=0.001, max=0.1) + # Electron injection, which is assumed to have a constant injection # rate and a power-law spectrum. injection_index = float(default=2.3, min=2.1, max=3.0) -- cgit v1.2.2