diff options
Diffstat (limited to 'fg21sim/extragalactic/clusters')
| -rw-r--r-- | fg21sim/extragalactic/clusters/halo.py | 59 |
1 files changed, 14 insertions, 45 deletions
diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py index ed05edf..b480b9c 100644 --- a/fg21sim/extragalactic/clusters/halo.py +++ b/fg21sim/extragalactic/clusters/halo.py @@ -256,7 +256,8 @@ class RadioHalo1M: return helper.radius_stripping(M_main, M_sub, z, f_rc=self.f_rc, beta=self.beta) - def tau_acceleration(self, t): + @lru_cache() + def tau_acceleration(self, t_merger): """ Calculate the electron acceleration timescale due to turbulent waves, which describes the turbulent acceleration efficiency. @@ -289,42 +290,13 @@ class RadioHalo1M: = X_cr * c_s^3 * (M_main/1e15)^(-m) / (8*f_acc * k_L * v_t^4) with: f_acc = f_m * ΞΆ - WARNING - ------- - Tests show that a very large acceleration timescale (e.g., - 1000 or even larger) will cause problems (maybe due to some - limitations within the current calculation scheme), for example, - the energy losses don't seem to have effect in such cases, so the - derived initial electron spectrum is almost the same as the raw - input one, and the emissivity at medium/high frequencies even - decreases when the turbulence acceleration begins! - By carrying out some tests, the value of 10 [Gyr] is adopted for - the maximum acceleration timescale. - - Parameters - ---------- - t : float, optional - The cosmic time when to determine the acceleration timescale. - Unit: [Gyr] - - Returns - ------- - tau : float - The acceleration timescale at the requested time. - Unit: [Gyr] - References ---------- * Ref.[pinzke2017],Eq.(37) * Ref.[miniati2015],Eq.(29) """ - # Maximum acceleration timescale when no turbulence acceleration - # NOTE: see the above WARNING! - tau_max = 10.0 # [Gyr] - if not self._is_turb_active(t): - return tau_max + self._validate_t_merger(t_merger) - t_merger = self._merger_time(t) L = 2 * self.radius_turbulence(t_merger) # [kpc] k_L = 2 * np.pi / L_turb cs = helper.speed_sound(self.kT(t_merger)) # [km/s] @@ -338,10 +310,7 @@ class RadioHalo1M: tau *= f_mass tau /= self.f_acc # tune factor (folded with "zeta_ins") - # Impose the maximum acceleration timescale - if tau > tau_max: - tau = tau_max - return tau + return tau # [Gyr] @property @lru_cache() @@ -530,13 +499,14 @@ class RadioHalo1M: Diffusion term/coefficient for the Fokker-Planck equation. The diffusion is directly related to the electron acceleration - which is described by the ``tau_acc`` acceleration timescale - parameter. + and calculated from the acceleration timescale ``tau_acc``. WARNING ------- A zero diffusion coefficient may lead to unstable/wrong results, since it is not properly taken care of by the solver. + By carrying out some tests, the maximum acceleration timescale + ``tau_acc`` is assumed to be 10 [Gyr]. Parameters ---------- @@ -551,15 +521,14 @@ class RadioHalo1M: diffusion : float, or float 1D `~numpy.ndarray` Diffusion coefficients Unit: [Gyr^-1] - - References - ---------- - Ref.[donnert2013],Eq.(15) """ - tau_acc = self.tau_acceleration(t) - gamma = np.asarray(gamma) - diffusion = gamma**2 / 4 / tau_acc - return diffusion + tau_acc = tau_max = 10.0 # [Gyr] + if self._is_turb_active(t): + t_merger = self._merger_time(t) + tau_acc = self.tau_acceleration(t_merger) + if tau_acc > tau_max: + tau_acc = tau_max + return np.square(gamma) / (4 * tau_acc) # [Gyr^-1] def fp_advection(self, gamma, t): """ |