IsothermalAtmosphere#

class MCEq.geometry.density_profiles.IsothermalAtmosphere(location, season, hiso_km=6.3, X0=1300.0)[source]#

Bases: EarthsAtmosphere

Isothermal model of the atmosphere.

This model is widely used in semi-analytical calculations. The isothermal approximation is valid in a certain range of altitudes and usually one adjust the parameters to match a more realistic density profile at altitudes between 10 - 30 km, where the high energy muon production rate peaks. Such parametrizations are given in the book “Cosmic Rays and Particle Physics”, Gaisser, Engel and Resconi (2016). The default values are from M. Thunman, G. Ingelman, and P. Gondolo, Astropart. Physics 5, 309 (1996).

Parameters:

location (str) – no effect
season (str) – no effect
hiso_km (float) – isothermal scale height in km
X0 (float) – Ground level overburden

Attributes Summary

`max_X`	Depth at altitude 0.
`max_den`	Density at altitude 0.
`s_X2rho`	Spline for conversion from depth to density.
`s_h2X`	Spline for conversion from altitude to depth.
`s_lX2h`	Spline for conversion from depth to altitude.

Methods Summary

`X2h`(X)	Returns the height above surface as a function of slant depth for currently selected zenith angle.
`X2rho`(X)	Returns the density \(\rho(X)\).
`calculate_density_spline`([n_steps])	Calculates and stores a spline of \(\rho(X)\).
`gamma_cherenkov_air`(h_cm)	Returns the Lorentz factor gamma of Cherenkov threshold in air (MeV).
`get_density`(h_cm)	Returns the density of air in g/cm**3.
`get_mass_overburden`(h_cm)	Returns the mass overburden in atmosphere in g/cm**2.
`h2X`(h)	Returns the depth along path as function of height above surface.
`moliere_air`(h_cm)	Returns the Moliere unit of air for US standard atmosphere.
`nref_rel_air`(h_cm)	Returns the refractive index - 1 in air (density parametrization as in CORSIKA).
`r_X2rho`(X)	Returns the inverse density \(\frac{1}{\rho}(X)\).
`set_h_obs`(h_obs)	Set the elevation of the observation (detector) level in cm.
`set_theta`(theta_deg)	Configures geometry and initiates spline calculation for \(\rho(X)\).
`theta_cherenkov_air`(h_cm)	Returns the Cherenkov angle in air (degrees).

Attributes Documentation

max_X#: Depth at altitude 0.

max_den#: Density at altitude 0.

s_X2rho#: Spline for conversion from depth to density.

s_h2X#: Spline for conversion from altitude to depth.

s_lX2h#: Spline for conversion from depth to altitude.

Methods Documentation

X2h(X)#

Returns the height above surface as a function of slant depth for currently selected zenith angle.

The spline s_lX2h is used, which was calculated or retrieved from cache during the set_theta() call.

Parameters:: X (float) – slant depth in g/cm**2
Returns:: height above surface in cm
Return type:: float h

X2rho(X)#

Returns the density \(\rho(X)\).

The spline s_X2rho is used, which was calculated or retrieved from cache during the set_theta() call.

Parameters:: X (float) – slant depth in g/cm**2
Returns:: \(\rho\) in cm**3/g
Return type:: float

calculate_density_spline(n_steps=2000)#

Calculates and stores a spline of \(\rho(X)\).

Parameters:: n_steps (int, optional) – number of \(X\) values to use for interpolation
Raises:: Exception – if set_theta() was not called before.

gamma_cherenkov_air(h_cm)#: Returns the Lorentz factor gamma of Cherenkov threshold in air (MeV).

get_density(h_cm)[source]#

Returns the density of air in g/cm**3.

Parameters:: h_cm (float) – height in cm
Returns:: density \(\rho(h_{cm})\) in g/cm**3
Return type:: float

get_mass_overburden(h_cm)[source]#

Returns the mass overburden in atmosphere in g/cm**2.

Parameters:: h_cm (float) – height in cm
Returns:: column depth \(T(h_{cm})\) in g/cm**2
Return type:: float

h2X(h)#

Returns the depth along path as function of height above surface.

The spline s_X2rho is used, which was calculated or retrieved from cache during the set_theta() call.

Parameters:: h (float) – vertical height above surface in cm
Returns:: X slant depth in g/cm**2
Return type:: float

moliere_air(h_cm)#: Returns the Moliere unit of air for US standard atmosphere.

nref_rel_air(h_cm)#: Returns the refractive index - 1 in air (density parametrization as in CORSIKA).

r_X2rho(X)#

Returns the inverse density \(\frac{1}{\rho}(X)\).

The spline s_X2rho is used, which was calculated or retrieved from cache during the set_theta() call.

Parameters:: X (float) – slant depth in g/cm**2
Returns:: \(1/\rho\) in cm**3/g
Return type:: float

set_h_obs(h_obs)#: Set the elevation of the observation (detector) level in cm.

set_theta(theta_deg)#

Configures geometry and initiates spline calculation for \(\rho(X)\).

If the option ‘use_atm_cache’ is enabled in the config, the function will check, if a corresponding spline is available in the cache and use it. Otherwise it will call calculate_density_spline(), make the function r_X2rho() available to the core code and store the spline in the cache.

Parameters:: theta_deg (float) – zenith angle \(\theta\) at detector

theta_cherenkov_air(h_cm)#: Returns the Cherenkov angle in air (degrees).