gridaurora

Grid for Auroral models

Discretizations of space (grids) and time conversions useful for aeronomy and auroral modeling.

Install

python -m pip install -e .

Note: you will need a Fortran compiler on your system for f2py modules. It works on Linux, Mac, Windows, etc.

Eigenprofiles

Currently GLOW and Rees-Sergienko-Ivanov are available (Transcar in future). You can install these models with

pip install -e .[models]

Once installed, select model by:

• -M rees Rees-Sergienko-Ivanov
• -M glow Stan Solomon's GLOW model

Command Line Options

-t time, format yyyy-mm-ddTHH:MM:SSZ where Z sets UTC time zone -c lat, lon WGS84 geodetic degrees -o output, hDF5 ends in .h5 -M model select (see table above) -z min,max altitude to plot [km]

Example Command

python MakeIonoEigenprofile.py -t 2013-01-31T09:00:00Z -c 65 -148 -o out.h5 -M rees

Auroral Data Files

The functions in gridaurora/calcemissions.py, based on work by Zettergren, computes per-wavelength volume emission rate along a flux tube as a function of altitude along the tube. Starting with quantities such as neutral densities computed by MSIS, differential number flux as a function of energy and altitude along the tube (this is what TRANSCAR computes), excitation cross sections as a function of energy, Franck-Condon factors and Einstein coefficients, the prompt volume emission rate may be computed.

precompute/vjeinfc.h5

This file is compiled from tables in Vallance Jones Aurora 1974 and other sources by Matthew Zettergren, and corrected and put into HDF5 format by Michael Hirsch. The information within concerns:

• N2+1NG: N2^+^ first negative group
• N2_1PG: N2 first positive group
• N2_2PG: N2 second positive group
• N2+Meinel: N2^+^ Meinel band
• atomic: atomic oxygen
• metastable: metastable O and O^+^

Einstein coefficient matrix A

arranged A(𝜈',𝜈'') where:

• 𝜈' upper state vibrational levels, excited from ground state 𝜈''' by particle impact
• 𝜈'' lower state vibrational levels, decayed into from the upper state

as discussed in Appendix C of Zettergren PhD thesis, Eqn. (C.2), photon volume emission rate follows the relation P𝜈',𝜈'' = A(𝜈',𝜈'') n𝜈'

lamdba

wavelength in nanometers corresponding to the Einstein coefficient matrix A except atomic that uses the reaction rates directly.

Franck-Condon factor fc

as described in Zettergren thesis Appendix C, specifically for Eqn (C.6-C.8), the Franck-Condon factors modify the total upper state excitation cross section multiplicitively.

Function Description

function	description
ztanh.py	continuously varying grid using hyperbolic tangent. Inspired by suggestion from Prof. Matt Zettergren of ERAU.