gridaurora 1.2.0

Gridding for auroral and ionospheric modeling

gridaurora

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

Contents

• gridaurora

  • Install

  • Eigenprofiles

    • Command Line Options

    • Example Command

  • Auroral Data Files

    • precompute/vjeinfc.h5

      • Einstein coefficient matrix A

      • lamdba

      • Franck-Condon factor fc

  • Function Description

  • References

Install

python -m pip install -e .

Note: you will need a Fortran compiler on your system so that f2py can work. Yes, it’s possible on Windows too.

Eigenprofiles

Currently GLOW and Rees-Sergienko-Ivanov are available (Transcar in future). You will need to separately install scivision/reesaurora and scivision/glowaurora. This is to keep the install process from becoming gigantic when you just want some of the models.

Once installed, select model by:

-M option	Model used
-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

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 P_{𝜈’,𝜈’’} = A(𝜈’,𝜈’’) n_𝜈’

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.

References

[1]

Zettergren, M. Boston University, PhD Thesis, http://search.proquest.com/docview/304847517