# Copyright (C) 2017, 2018 Luiz Felippe S. Rodrigues <luiz.rodrigues@ncl.ac.uk>
#
# This file is part of GalMag.
#
# GalMag is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GalMag is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GalMag. If not, see <http://www.gnu.org/licenses/>.
#
"""
Distributions of electron densities and cosmic ray densities
"""
import numpy as np
[docs]def simple_ne(rho, theta, phi, ne0=1.0, Rs=2.6, R_d=1.0, Rsun=8.5, **kwargs):
r"""
Simple electron density profile
Comprises a exponential flared disc.
.. math::
n = n_0 \exp\left[-\frac{r \sin(\theta)-s_\odot}{s_s}\right] \exp\left[\frac{-r \cos(\theta)}{h(s)}\right]
where :math:`h(s)` is given by
:func:`galmag.disk_profiles.exponential_scale_height`
Parameters
----------
rho : array
Spherical radial coordinate, :math:`r`
theta : array
Polar coordinate, :math:`\theta`
phi : array
Azimuthal coordinate, :math:`\phi`
ne0 : float
Number density at `Rsun`. Default: 1.0
R_d : float
unit of `rho` in kpc [e.g. R_d=(disk radius in kpc)
for r=0..1 within the disk]. Default: 1.0
Rs : float
Scale radius, :math:`s_s`, of the disc in kpc. Default: 2.6 kpc
Rsun : float
Reference radius, :math:`s_\odot`, in kpc. Default: 8.5 kpc
"""
from galmag.disk_profiles import exponential_scale_height
# Cylindrical radius
R = rho*np.sin(theta)*R_d
z = rho*np.cos(theta)*R_d
h = exponential_scale_height(R, R_d=1.0, Rsun=8.5, **kwargs)
ne = ne0 * np.exp(-(R-Rsun)/Rs) * np.exp(-np.abs(z)/h)
return ne
[docs]def constant_ne(rho, theta, phi, ne0=1.0):
"""
Dummy for constant cosmic ray electron density
"""
ne = np.empty_like(rho)
ne[:,:,:] = ne0
return ne
[docs]def constant_ncr(rho, theta, phi, ncr0=1.0):
"""
Dummy for constant cosmic ray electron density
"""
ncr = np.empty_like(rho)
ncr[:,:,:] = ncr0
return ncr